What Do P-Values Really Mean?

This month’s blog theme is nursing research, so I’m discussing the meaning of some statistical concepts to help you interpret the research studies you are reading. I’m going to talk about several concepts this month that I have found both undergraduate and graduate students struggle to really understand. Last week I presented the difference between statistical significance and clinical significance. Today’s post is all about alpha levels, AKA p-values.

“Statistics means never having to say you’re certain.” Anonymous
Learning statistics (AKA stats) is the bane of many a nursing student’s life! Not only do you have to have a basics stats course before you are admitted to a baccalaureate nursing program, but you have to take statistics again in your graduate program!

Why do faculty make you learn about the research process, hypothesis testing, data analysis, likelihood ratios, relative risks, p-values, and the like?

Because as a professional nurse you are expected to care for patients using the most current, evidence-based knowledge and interventions to promote positive patient outcomes.

Part of that responsibility entails you critically examining the research literature upon which your nursing practice is based.

You can’t confidently examine that literature without a basic understanding of the research process and the methods researchers use to ensure accurate results. And you have to have a basic understanding of what the results mean.

Before we talk about the p-value, let’s understand what the researchers are testing, first. Quickly, let’s review hypothesis testing.

What is Hypothesis Testing?
Scientists conduct research to, hopefully, show that their intervention, for example, is more effective or better than the status quo. So they come up with their research hypothesis that A (their intervention) is not the same as the standard of care (SOC). The status quo or SOC is called the null hypothesis (H0).

The research or alternative hypothesis is identified as H1. The research hypothesis can be written as different than the SOC (H1 ≠ H0) if the researcher is not sure in which direction the finding will go (positive or negative). Or with previous research support, the researcher could declare the research hypothesis as going in a certain direction, such as better than the SOC (H1 > H0).

The null hypothesis is always assumed to be true. So how does a researcher demonstrate that H1 is different from H0? They have to disprove the assumption that the null hypothesis is true! So the researcher wants to reject the null hypothesis; so that he can accept the research hypothesis. Does that make sense? Because negatively worded phrases can be confusing – we understand positively worded phrases better – this understanding is a big stumbling block for students.

So basically, the researcher tests these hypotheses to see which condition is true for their study. Is the null hypothesis that the SOC and the intervention have the same effect true (H1 = H0)? Is so, the test statistic should have a p-value of greater than the a priori alpha level. The researcher can’t declare the intervention different than the SOC and the research finding is reported as not significant.

Or is the intervention different than the SOC and therefore true (H1 ≠ H0)? If the research hypothesis is different or better, then a p-value of the test statistic should be less than the alpha level; the researcher will declare victory and label the research finding as statistically significant.

Finding out the answers to these questions is called hypothesis testing. You compare the null hypothesis to the research hypothesis. There are only two decisions that the researcher can make when testing hypotheses: either the null is true and the intervention is deemed not to work differently than the SOC or the intervention works differently and the null is false.

Research and the “Truth”
While this seems like a fairly straightforward process, what you should remember is that whatever decision the researchers make may be wrong! The reason is that the researchers are using estimates. And even though the probability may be low that the research result is a function of chance alone for p<0.05, there is still a chance that that particular study is one of the 5 in 100 (or 1 in 100, 1 in 1000, etc. for other p-values) that is significant because of random error.

Here’s the kicker: the researchers will never know whether their study is one of 5 in 100 that shows a false positive! All they can do is conduct their study as rigorously as possible, enter the data into the statistical program they are using, run the statistical tests, and report the results. They will report what they get and make their conclusions based on their a priori alpha levels (the results were not statistically significant; there was a statistically significant difference …). The way to generate confidence that the results are true is to replicate the study and hope for similar statistical results.

What happens if a statistical test comes back with a p-value of 0.05? If the a priori p-value is <0.05, then the researcher cannot reject the null hypothesis because the result is not less than 0.05, right? P-values near 0.05 are frequently considered “weak” evidence against the null hypothesis, but the American Statistical Association (ASA) has rebutted this misconception by stating that a p-value by itself should not be used as evidence for or against the null hypothesis (ASA, 2016).

But, apparently, there is a rising trend among researchers, especially in the social sciences, to declare p-values in the range of 0.05-0.10 as “marginally significant.” They may also use the term “approaching significance” (APS, 2016; Pritschet, Powell, & Horne, 2016). The Pritschet et al. study presents reasons for how this type of thinking can lead researchers astray.

The probability that the research results are not a function of random error is called the significance level.

Probability and Significance
In last week’s post on significance, I defined statistically significant as “probably caused by something other than mere chance.”

The significance level is known as the alpha level and it is used to signify the probability of a result occurring from the research study that is “caused by something other than mere chance.” P is short for probability, hence p-values.

The p-value is the probability of making the wrong decision when the null hypothesis is really true. The p-value is set by the researcher before the study begins as an objective measure of uncertainty.

The p-value is the probability of making the wrong decision (i.e., to reject the null) when the null hypothesis is really true.
Researchers want their research findings to be significant, of course! Statistically significant research results are more likely to get funded and published than research studies with non-significant findings (Frost, 2014). So that p-value wields great power!

How Does the P-Value Get Chosen?
The p-value is the value at which you reject the null hypothesis or how much evidence do you have against the null hypotheses? The evidence is the data you enter from your study and submit to statistical testing. The p-value is a single cut-off point for deciding whether to reject the null hypothesis.

The choice of which p-value to use is arbitrary – there is no universal rule for when to choose a p-value of <0.05 or p < 0.01: the researcher chooses the p-value they want. The researcher needs to decide how must uncertainty they are willing to allow to declare their intervention a success, once the data have been entered and the statistical tests have been run. There are some criteria the researcher considers when choosing the p-value for their study — like which statistical error is more important to prevent (a Type I error or a Type II error) — but we will talk about this concept another time.

Many researchers, especially in nursing and the social sciences, set the alpha level at p < 0.05. What does this mean? This means the researcher is willing to take a chance that their statistical result will be wrong 5% of the time. They are willing to incorrectly state that their intervention is different from the SOC, when it’s really not, 5 out of 100 times. So if the study was replicated 20 times, only once would they reject the null hypothesis when it was really true. If the study was repeated 100 times, they would incorrectly reject the null five times.

When the outcome stakes are higher, as in a drug study, you may see the alpha level set at p < 0.01 or less. The researchers will want to decrease the uncertainty of a false positive because a higher level of uncertainty could mean that an ineffective drug may take the place of an effective drug. So if the study was replicated 100 times, only once would they reject the null hypothesis when it was, in reality, true.

One more thing: let me clarify “Reality” or “Truth.” Unless you can test the entire population with a specific disease — heart failure, let’s say — we can’t know for sure how the entire population will react to an intervention. This would be a very expensive study to conduct and it just wouldn’t happen, so we can’t know the population mean from which to make decisions for our patients. So instead we use representative samples and statistical testing to get to a result that we can then generalize to the entire population.

Samples are an estimation for the population, the statistic is also only an estimate; therefore, if you drew a different sample, you’d get a different value. No matter how carefully this sample is selected to be a fair and unbiased representation of the population, relying on information from a sample will always lead to some level of uncertainty (Simon, n.d.). The p-value helps the researcher to decrease that level of uncertainty, but it doesn’t eliminate uncertainty altogether.

P-Values and Uncertainty
There are two accepted understandings of the p-value: (a) that the p-value shows how strong the evidence is against the null hypothesis — for example, p-value of < 0.0001 is stronger than a p-value of H0).
This is the hypothesis the researchers hope to ACCEPT.
The p-value is set at p < 0.05.
The researchers do a power analysis and choose a representative sample. They conduct their study and collect their data. The data are entered into a statistical program and the statistical tests are run. The researchers will report the test statistic results they get and make their conclusions based on their a priori alpha levels (the results were not statistically significant; there was a statistically significant difference …).

Research data is analyzed with computers. Therefore, the statistical programs researchers use will give them an actual p-value instead of just a “< 0.05” result. For example, a p of 0.028, .052, or 0.18, will most likely be reported as the actual result. We still interpret statistical significance of that result as compared to the alpha level set by the researcher.

For example, a statistical test provides a p of 0.028. This would be considered statistically significant if the alpha level was set as p < 0.05 (because 0.028 is less than 0.05, right?); however, if the alpha level was set at p < 0.01, then p = 0.028 would not be statistically significant (because 0.028 is greater than 0.01). The values of 0.052 and 0.18 would not be statistically significant using either p-value because they are both greater than 0.05 or 0.01. Remember that “marginally significant” or “approaching significance” doesn’t fly!

Don’t be fooled into thinking that a p-value of .001 is less significant than a p-value of .0001. (Another way to say that is to think that the smaller p-value of p = 0.0001 is stronger or more significant than the p-value of 0.001.)

All this result tells you is that, for the observed sample, a study result of p = 0.0001 is 100 times less likely to be a result of chance than the p = 0.001. It is more incompatible with the truth of the null hypothesis than the p of 0.001, but it doesn’t mean that the research hypothesis is definitely true!

P-values do NOT tell you that one hypothesis is True and the other not! The only thing the p-value tells you is how improbable the research result is in the context of an assumed true null hypothesis (Altman & Kryzwinski, 2017; Frost, 2014).

If you accept the null hypothesis, it just means that the evidence from your study was not strong enough to disprove the assumption that the intervention is significantly different from the SOC (Shorten & Shorten, 2013).

Nursing Application of The Principle of Uncertainty

Because we don’t know what the “Truth” about a population really is (that is, the population mean), and we are depending on statistical estimates, you should NOT use the results of just one “statistically significant” study to change your nursing practice!

How do we make a decision about using research in practice? We look for more than one study with similar findings. The more studies that point toward the same result – the more confident you can be that while one study may be the random error, two studies showing the same statistically significant results is less likely to be random error, three studies even less likely, etc.

What are your questions after reading this post about p-values? Let me know in the comments!

Altman, N., & Krzywinski, M. (2017). Points of significance: Interpreting P values. Nature Methods, 14, 213–214. doi:10.1038/nmeth.4210

Association for Psychological Science (APS). (2016, May 20). Rise in reporting p-values as “marginally significant.” Retrieved from http://www.psychologicalscience.org/publications/observer/obsonline/rise-in-reporting-p-values-as-marginally-significant.html#.WPZREYjyuCg

Frost, J. (2014, April 17). How to correctly interpret p values. Retrieved from http://blog.minitab.com/blog/adventures-in-statistics-2/how-to-correctly-interpret-p-values

Halsey, L. G., Curran-Everett, D., Vowler, S. L., & Drummond, G. B. (2015). The fickle P value generates irreproducible results. Nature Methods 12, 179–185. doi:10.1038/nmeth.3288

Pritschet, L., Powell, D., & Horne, Z. (2016). Marginally significant effects as evidence for hypotheses: Changing attitudes over four decades [Abstract]. Psychological Science, 27, 1036 – 1042.

Royal Statistical Society. (2016, November 15). ASA statement on P-values and statistical significance: Development and impact [YouTube Presentation]. Retrieved from https://www.youtube.com/watch?v=B7mvbOK1ipA

Shorten, A., & Shorten, B. (2013). Hypothesis testing and p values: How to interpret results and reach the right conclusions. Evidence-Based Nursing, 16(2), 36-37. doi:10.1136/eb-

Pick one of your traits and explain the influences that both nature and nurture have on it.

Module 2 Discussion Questions

· Pick one of your traits and explain the influences that both nature and nurture have on it. For example, if you have a short temper, explain its origins in your genetics, your culture, and your childhood experiences.

2. Module 3 Discussion Questions

· Programs like Head Start aimed at providing cognitive enrichment for children growing up in impoverished areas are focused on children ages 3-5. The newer works on brain development, however, suggest that this may be too late. Do you think enrichment programs for infants would make more sense? Are such programs likely to be socially acceptable or practically feasible?

3. Module 4 Discussion Questions

· Is it possible to overemphasize the importance of secure attachment? Why or why not? Consider this video when formulating your response: : Trauma, Brain & Relationship: Helping Children Heal (Links to an external site.)Links to an external site.

4. Trauma, Brain & Relationship: Helping Children Heal The Post Institute

5. Module 5 Discussion Question

· Given the degree of variability, discuss your position in regards to whether it makes sense to select children for special classes for the gifted on the basis of a single test score? How else could you go about it?

College Admissions Essay Growing In Meaningful And Impactful Ways (Essay Sample)

The year 2024 will mark USD’s 75th anniversary. In preparation for this milestone, we as a campus community are looking to grow in meaningful and impactful ways. We are looking to set the standard for an engaged, contemporary Catholic university where innovative changemakers confront humanity’s urgent challenges. In what ways do you hope to grow by the year 2024? Where do you see yourself, and what type of impact do you hope to have on the world around you?

The importance of baseline observation in Nursing practice


Learning Outcome One: You will identify what effective communication is, how it is used in nursing, and reflect on the strengths and weaknesses of your own communication skills. You will also consider your own personal values and beliefs, and how these may impact on the care you give or approach to service users in the future and in light of recent reports and legislation.

Learning Outcome Two: Nurses are bound by a professional code of conduct, which sets out the way in which all registered nurses must behave. You will discuss the content of this code and how it is applied in nursing practice. Think about the NHS constitution, the 6 Cs, the Francis Report of 2013, and the Keogh enquiry of 2013.


You will need to identify and consider your personal learning during this module to encompass learning outcomes one and two; this could be a new skill, the development of a previously learnt skill, or an aspect of theoretical knowledge that is new to you. You need to consider why this topic was important, and what its impact on you, this will enable you to identify strategies to develop your topic further. You MUST incorporate aspects of the NHS Constitution and the 6Cs into this essay in order to demonstrate your knowledge and understanding of the professional nature of nursing.

“This essay can be written in the First Person or Passive”


**The introduction should signpost your topic choice and areas to be discussed. The main body of the discussion should address the following issues
Ø **Clearly identify your new learning, giving a rationale for your choice.
Ø **How has this learning made a difference to you?
Ø **How will this learning influence your future clinical practice?
Ø **Describe how you will continue to develop this learning after this module.
Ø **How does this personal/professional development relate to the NMC Code?
Ø **How does your topic relate to the NHS Constitution and the 6 Cs
The importance of effective communication, in relation to your new learning, can be explored at any point within the essay.

**The essay should finish with a clear conclusion which draws together the themes of discussion and identifies with learning outcomes 1 and 2.

Remember to use use only united kingdom evidence based article , journal. book like NICE etc. Also pls do not use big grammers(avoid big vocabularly).

challenging or difficult event from your nursing practice

Select a challenging or difficult event from your nursing practice. Use one of the theories presented in this module to analyze that event and provide insight for how this type of event might best be managed in the future. For example, you may be frustrated by physicians who refuse to use the computer and ask you to look up their patients. You might use change theory, Rogers’s theory of innovation or learning theory to analyze the event and suggest an effective approach for dealing with this issue? Review the post of other classmates and comment on the analysis and selected approach for dealing with the issue.


Assignment 2: Inventory Management Due Week 8 and worth 300 points
Research two (2) manufacturing or two (2) service companies that manage inventory and complete this assignment. Write a six to eight (6-8) page paper in which you:

Determine the types of inventories these companies currently manage and describe their essential inventory characteristics.
Analyze how each of their goods and service design concepts are integrated.
Evaluate the role their inventory plays in the company’s performance, operational efficiency, and customer satisfaction.
Compare and contrast the four (4) different types of layouts found with each company; explain the importance of the layouts to the company’s manufacturing or service operations.
Determine at least two (2) metrics to evaluate supply chain performance of the companies; suggest improvements to the design and operations of their supply chains based on those metrics.
Suggest ways to improve the inventory management for each of the companies without affecting operations and the customer benefit package. Provide a rationale to support the suggestion.
Use at least three (3) quality resources in this assignment. Note: Wikipedia and similar Websites do not qualify as quality resources.
Your assignment must follow these formatting requirements:

Be typed, double spaced, using Times New Roman font (size 12), with one-inch margins on all sides; citations and references must follow APA or school-specific format. Check with your professor for any additional instructions.
Include a cover page containing the title of the assignment, the student’s name, the professor’s name, the course title, and the date. The cover page and the reference page are not included in the required assignment page length.
The specific course learning outcomes associated with this assignment are:

Evaluate the processes used in designing and producing goods and services.
Determine four layout patterns and when they should be used.
Utilize the concept of supply chain management.
Employ the concept of capacity management.
Evaluate the management of inventories and resources.
Use technology and information resources to research issues in operations management.
Write clearly and concisely about operations management using proper writing mechanics.

Discuss the challenges that incident handlers face in identifying incidents when resources have been moved to a cloud environment.  

Discuss the challenges that incident handlers face in identifying incidents when resources have been moved to a cloud environment.  

DQ requirement: Note that the requirement is to post your initial response no later than Thursday and you must post one additional post during the week. I recommend your initial posting to be between 200-to-300 words.

leading factor of death in adults worldwide

A heart attack or Myocardial infarction (MI) is the leading factor of death in adults worldwide (Nicolai et al., 2018).  MI occur in patients when the blood flow to the heart is blocked due to increased built of plaque within the walls of the blood vessels. Patients can experience sharp, sudden pain or heaviness in their chest as the first sign when experiencing an MI.  This pain can be in the chest and move up to the jaw and down the left arm. When blood flow is decreased to the heart, there is an insufficient amount of oxygen supplied to the heart, and the electrolyte become imbalanced specifically potassium, calcium, and magnesium.  The heart can only handle the blood, oxygen, and electrolyte imbalances for twenty minutes before tissue begins to die, at this point is the damage is irreversible (Huether & McCance, 2017). As an advanced practice nurse, an Electrocardiogram (ECG) would be first in diagnosing techniques. Depending on the results of the ECG will help determine how to treat the patient. If the ECG showed ST elevation, this means the patient needs to get to a cardiac catheterization lab urgently. If the ECG results within reasonable limits, treating the chest pain would be the next appropriate step.  Medication used to treat stable chest pain are called nitrates. The most common name is nitroglycerin. The medication is placed underneath the tongue where it dissolves and should relieve the pain within one to five minutes (Arcangelo, Peterson, Wilbur, & Reinhold, 2017).  When the ECG indicates a STEMI, a thrombolytic medication should be initiated to dissolve any blood clots in the arteries (Avoiding, 2005). A standard medication used in my patient care experience is heparin which is first based on weight for the first six hours of treatment. After six hours labs are drawn on the patient to determine whether the rate should be titrated up or down. After patient returns from cardiac catheterization lab, cardiology doctors can provide guidance on how to proceed with the proper medications for the patient.
Genetics and Ethnicity
If your parents have had an MI, does it mean you will have one? Likely the answer is no; research has shown necessarily doesn’t say you will but have found a link among ethnicity in Europeans, South Asians, Southeast Asians, and Arabs (Joseph et al., 2016). Specifically, there’s no genetic link to an MI but rather coronary artery disease (CAD) which can lead to MI.  However modifiable risk factors, such as a healthy lifestyle, prove to be the most significant way to decrease the risk of an MI.
After a patient experiences an MI, usually, they are set up to attend a Cardiac rehabilitation program. This program helps the patient get back to a healthy lifestyle while incorporating changes to prevent an MI in the future. Advanced practice providers should closely watch patients with hypertension, diabetes, and hyperlipidemia. Research has shown if a patient has two out three diagnoses they are at higher risk for a heart attack (Avoiding, 2005). Encouraging physical activity, a healthy diet, and smoking cessation are critical factors in patient education. Studies suggest educating patients on doing at least thirty minutes of activity a day such as walking, gardening, or housework also to cut out fast food that is high in fat and sugary drinks (Advance et al., 2005).
Arcangelo, V. P., Peterson, A. M., Wilbur, V. & Reinhold, J. A.  (Eds.). (2017). Pharmacotherapeutics for advanced practice: A practical approach (4th ed.). Ambler, PA:  Lippincott Williams & Wilkins.
Avoiding heart attacks and strokes. [electronic resource]: don’t be a victim – protect yourself. (2005). Geneva: World Health Organization, c2005.
Huether, S. E., & McCance, K. L. (2017). Understanding pathophysiology (6th ed.). St. Louis, MO: Mosby.
Joseph, P. G., Pare, G., Asma, S., Engert, J. C., Yusuf, S., & Anand, S. S. (2016). Clinical Research: Impact of a Genetic Risk Score on Myocardial Infarction Risk Across Different Ethnic Populations. Canadian Journal Of Cardiology, 321440-1446. doi:10.1016/j.cjca.2016.05.014
Nicolai, J., Müller, N., Noest, S., Wilke, S., Schultz, J., Gleißner, C. A., & … Bieber, C. (2018). To change or not to change – That is the question: A qualitative study of lifestyle changes following acute myocardial infarction. Chronic Illness, 14(1), 25-41. doi:10.1177/1742395317694700
The post APA format for MSN degree 2 references from Walden University Library

Refer to the attach file for writing on activity 12.23

Refer to the attach file for writing on activity 12.23
Order Description
Complete activity 12.23. Choose a piece of equipment that would be needed in a business (do NOT choose copiers, computers, or cell phones). Your research might include interviews with individuals (users, owners, salespeople, technicians, fellow employees,etc.) in a position to comment on the attributes of the equipment, and information in print form or electronic sources, such as magazine articles, company web sites, or owner manuals.
Components : Introduction, body, conclusions, recommendations, bibliography. Report must also include at least one meaningful visual component (graph, chart, picture, etc.). [Note: Although the text sample does not show a bibliography page, you must have one showing all your sources of information.
Information Sources : A minimum of three sources including at least one primary source and one Internet source. (A primary source would be a personal interview, a survey you conducted, a demonstration you observed, trying the equipment yourself, etc.)
Formatting : Use memo format for this informal business report.

Educational issues from the perspective of business economics major

Education is a broad term but it generally refers to the process of learning and acquiring information, which can be either through formal learning like in schools or universities or through informal learning like the kind we get in “life experiences.” Countries around the world place a high value on education, particularly the formal kind, as it is widely believed that it makes people more productive and better contributors to society. As public policy, debates about education range from issues of curriculum design and implementation, allocation of money and resources, labor disputes between administrators and teachers, and education’s role in addressing racial and gender discrimination.


Research an educational issue from the perspective of a researcher in your own major field. For example, a major in sociology might investigate how a certain educational policy could affect society. A psychology major could examine a particular role of psychologists in education. A computer scientist might research how computers or online classes are changing the face of education. A history major could present an historical look at an educational issue. A business or economics major could examine the way an educational institutional could be made on the business model. A political science or world cultures major could compare different education systems. An art major could look at the importance of art as part of the general requirements in an education system.

An additional option would be that any major could also look at how his or her own major views education within that discipline, like how their own major should be taught. For example, a major in engineering could look at how people in that discipline view the way the new generation of engineers should be taught or trained, or a business major might discuss the issue of whether business ethics should play a bigger role in MBA programs.

Your research may result in an argumentative essay depending on your topic, but it does not have to. Instead, you may focus on informing your reader about a relatively unknown aspect of the education debate and its significance.

The goal of your essay is to inform your readers (your classmates) about one way that your field is connected to education or an educational issue that you choose to focus on. This essay will require you to conduct library research and acknowledge sources using the MLA or APA research format.


You will need to provide background information or context for the educational topic you have chosen. You will also need to present and integrate research on this topic and its connection to your field of study. You may include class readings among your sources. You will need to develop a thesis that is supportable with your research.

You must use a minimum of five sources by the final draft. The final draft will include an abstract and an annotated bibliography and be submitted on turnitin.com.

Page Limits: 8-10 pages, not including the abstract, works cited or annotated bibliography