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Hypothesis Testing and Correlation Worksheet

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					                                                                           STAT/167 Statistics for the Life Sciences




University of Phoenix Material
                       Hypothesis Testing and Correlation Worksheet
Answer the following questions. For questions requiring material from Statdisk, make sure to turn
labels on, take a screen capture (CTRL-Print Screen on most Windows-based computers), and
paste the image into the worksheet. Crop the image as appropriate.

For questions 1-4, please respond in a paragraph of no more than 100 words for each question.
1. What is a hypothesis? What is a hypothesis test (0.5 point)?
2. What is a null hypothesis? What is an alternative hypothesis (0.5 point)?
3. What is a test statistic (0.5 point)?
4. What are significance levels (0.5 point)?
5. Complete this table contrasting the traditional, p-value, and confidence interval methods of
   testing a claim about a proportion (1 point).


                                    Traditional                     p-value                Confidence Interval

 How would you use
 this method?


 Why would you use
 this method?

 What is an
 example of when
 this would be used
 in life sciences
 research?


Use the following description and table to answer questions 6-10.

A pharmaceutical company wants to determine if there is a significant reduction in heart rate with
their new drug, Clardozan, at the .01 level of significance. The researchers took a random sample
of 30 adults and randomly selected each to receive either Clardozan or the placebo. Heart rates
for each subject and treatment group are presented below; assume data are normally distributed
with equal variances.

    Subject           Clardozan              Subject             Placebo
                      Heart Rate                                Heart Rate
        1                 81                     2                  78
        4                 60                     3                  88
        7                 91                     5                  63
        8                103                     6                  56
       10                 85                     9                  70
       13                 88                    11                  77
Adapted from Biostatistics for the Biological and Health Sciences faculty materials with permission from Pearson Addison-
Wesley.


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                                                                           STAT/167 Statistics for the Life Sciences



       14                  84                   12                   64
       16                  60                   15                   48
       17                  60                   18                   51
       19                  72                   20                   52
       23                  96                   21                   76
       24                  75                   22                   80
       26                  58                   25                   51
       29                  70                   27                   66
       30                  81                   28                   55

6. What is the independent variable? What is the dependent variable? Why (0.5 point)?
7. What is the null hypothesis? What is the alternative hypothesis? Is this a one-tailed or a two-
   tailed test (0.5 point)?
8. What test statistic will you use? Why (0.5 point)?
9. What is the critical value? What is the value of the test statistic (0.5 point)?
10. Would you accept or reject the null hypothesis? Explain your conclusion in a 100- to 150-
    word summary (0.5 point).

Use the following description and table to answer questions 11-14.

More men than women were randomly assigned to the Clardozan group. After a careful
examination of the results, the pharmaceutical company wonders if gender influenced the results.
Conduct a test to determine if there was a relationship between gender and group assignment
using the .05 level of significance. The 2 x 2 contingency table presented below shows subject
assignment by treatment group and by gender.
                                         Male                         Female
       Clardozan                           9                              6
        Placebo                            7                              8

11. What is the null hypothesis? What is the alternative hypothesis? Is this a one-tailed or a two-
    tailed test (0.5 point)?
12. What test statistic will you use? Why (0.5 point)?
13. What is the critical value? What is the value of the test statistic (0.5 point)?
14. Would you accept or reject the null hypothesis? Explain your conclusion in a 100- to 150-
    word summary (0.5 point).
15. What is the F distribution? Describe it in no more than 100 words (0.5 point).
16. How and when do researchers use the F distribution? Explain in no more than 150 words (0.5
    point).
17. What does it mean if F = 1.0251? Explain in no more than 150 words (0.5 point).
Use the following information to answer questions 18-19. Using Data Set 1 in Appendix B of the
text (Data Set: Health Exam Results, Female Health, Part I in Statdisk), determine the correlation
between women’s age and women’s weight.
18. Calculate r using Statdisk. Paste the Correlation and Regression report into your response.
    What is r (0.5 point)?



Adapted from Biostatistics for the Biological and Health Sciences faculty materials with permission from Pearson Addison-
Wesley.


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                                                                           STAT/167 Statistics for the Life Sciences


                        2
19. Interpret r and r . Explain whether there is a significant correlation between women’s age and
    women’s weight at the 0.05 significance level, and explain how much of the variation in
    women’s weight is explained by its linear association with women’s age (0.5 point).




Adapted from Biostatistics for the Biological and Health Sciences faculty materials with permission from Pearson Addison-
Wesley.


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