What does statistical significance mean? How do you know if something is statistically significant? What is the difference between statistical significance and practical significance?

Complete Parts A, B, and C below.

Part A

Why is a z score a standard score? Why can standard scores be used to compare scores from different distributions? Why is it useful to compare different distributions?

For the following set of scores, fill in the cells. The mean is 74.13 and the standard deviation is 9.98.

Raw score Z score
68.0 ?
? –1.6
82.0 ?
? 1.8
69.0 ?
? –0.5
85.0 ?
? 1.7
72.0 ?

Questions 3a through 3d are based on a distribution of scores with and the standard deviation = 6.38. Draw a small picture to help you see what is required.

What is the probability of a score falling between a raw score of 70 and 80?
What is the probability of a score falling above a raw score of 80?
What is the probability of a score falling between a raw score of 81 and 83?
What is the probability of a score falling below a raw score of 63?

Jake needs to score in the top 10% in order to earn a physical fitness certificate. The class mean is 78 and the standard deviation is 5.5. What raw score does he need?

Part B

The questions in Part B require that you access data from the Pulse Rate Dataset.

The data is based on the following research problem:
Ann conducted a study on the things that may affect pulse rate after exercising. She wants to describe the demographic characteristics of a sample of 55 individuals who completed a large-scale survey. She has demographic data on the participants’ gender (two categories), their age (open ended), their level of exercise (three categories), their height (open ended), and their weight (open ended).

Using Microsoft® Excel® software, run descriptive statistics on the gender and level of exercise variables. From the output, identify the following:

Percent of men
Mode for exercise frequency
Frequency of high level exercisers (exercise level 1) in the sample

Using Microsoft® Excel® software, run descriptive statistics to summarize the data on the age variable, noting the mean and standard deviation. Copy and paste the output from Microsoft® Excel® into this worksheet.

Part C

Answer the questions below in at least 90 words. Be specific and provide examples when relevant.

Cite any sources consistent with APA guidelines.

Question Answer
How does understanding probability help you understand inferential statistics?
When have you used probability in everyday life? How did you use it?
Which do you think would be a more serious violation: a Type I or Type II error? And why?
What are the characteristics that separate parametric and nonparametric tests?
What does statistical significance mean? How do you know if something is statistically significant? What is the difference between statistical significance and practical significance?

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