Null and Alternative Hypotheses for a Mean

At the heart of research lies a question. For example, consider the following scenario: you just went for a run in the park, and you feel great. Naturally, you might ask yourself "does exercise make people happy?". If you are asking a question that you don't know the answer to, research is necessary to resolve it. There are many forms that this research can take, from a literature review to performing an experiment. A technique known as statistical hypothesis testing is often used in psychology to determine a likely answer to a research question.

The sample size (N) is the total number of observations in the sample.

In the olden days, when people looked up P values in printed tables, they would report the results of a statistical test as "PPP>0.10", etc. Nowadays, almost all computer statistics programs give the exact P value resulting from a statistical test, such as P=0.029, and that's what you should report in your publications. You will conclude that the results are either significant or they're not significant; they either reject the null hypothesis (if P is below your pre-determined significance level) or don't reject the null hypothesis (if P is above your significance level). But other people will want to know if your results are "strongly" significant (P much less than 0.05), which will give them more confidence in your results than if they were "barely" significant (P=0.043, for example). In addition, other researchers will need the exact P value if they want to combine your results with others into a .

for testing the null hypothesis

The short answer is, as a scientist, you are required to; It’s part of the scientific process. Science uses a battery of processes to prove or disprove theories, making sure than any new hypothesis has no flaws. Including both a null and an alternate hypothesis is one safeguard to ensure your research isn’t flawed. Not including the null hypothesis in your research is considered very bad practice by the scientific community. If you set out to prove an alternate hypothesis without considering it, you are likely setting yourself up for failure. At a minimum, your experiment will likely not be taken seriously.

Frequentist Hypothesis Tests, p-values, and Type I Error

The t-distribution is more spread out than the normal curve. Therefore the proportion of area beyond a specific value of t is greater than the proportion of area beyond the corresponding value of z. The tails are fatter.

Frequentist Hypothesis Tests and p-values ..

Hold your pointer over the fitted distribution line to see a chart of percentiles and values. However, be aware that these values are accurate only if the data follow a normal distribution.

Hypothesis tests about the mean - Statlect

You’ll be asked to convert a word problem into a hypothesis statement in statistics that will include a null hypothesis and an . Breaking your problem into a few small steps makes these problems much easier to handle.

Hypothesis tests about the mean

The proportion of areas beyond a particular positive t-value is equal to the proportion of area below a corresponding negative t-value, just like the normal distribution

Null and Alternative Hypothesis | Real Statistics Using …

In many statistical tests, you’ll want to either reject or support the . For elementary statistics students, the term can be a tricky term to grasp, partly because the name “null hypothesis” doesn’t make it clear about what the null hypothesis actually is!

How to Determine a p-Value When Testing a Null Hypothesis

where the observed sample mean difference, μ0 = value specified in null hypothesis, sd = standard deviation of the differences in the sample measurements and n = sample size. For instance, if we wanted to test for a difference in mean SAT Math and mean SAT Verbal scores, we would random sample subjects, record their SATM and SATV scores in two separate columns, then create a third column that contained the differences between these scores. Then the sample mean and sample standard deviation would be those that were calculated on this column of differences.