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1. A survey to 52 students taking an introductory statistics class. One professo

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Question

1.A survey to 52 students taking an introductory statistics class. One professor hypothesized that women enter graduate school at an earlier age than men. To test this hypothesis a two independent sample t-test was utilized based on the survey data from 52 students. Note that the investigators did not believe the hypothesis from the professor so they utilized a two-tailed alternative hypothesis. Use the output in the Appendix to answer these questions.                                                      

Are the variances of age homogenous (equal) between males and females? Provide the justification (i.e. things in the SAS output) for your answer.

b.   What is the test statistic for the two-sample t-test? Give the actual number.

c.   Based on a confidence interval (CI) provided in the output, does mean age differ by gender? Provide the CI and justification for your answer.

d.   Based on a p-value provided in the output, does mean age differ by gender? Provide the p-value and justification for your answer.

e.   Does this data support the professor’s hypothesis that women enter graduate school earlier than men? Why or why not?

Use this data to answer the questions

Question 1

                                                                        The TTEST Procedure

                                          Variable: age

          gender          N        Mean     Std Dev     Std Err     Minimum     Maximum

          Female         21    27.0952      7.4088      1.6167     19.0000     48.0000

          Male           31     29.8387     11.1925      2.0102     20.0000     62.0000

          Diff (1-2)            -2.7435      9.8550      2.7853

gender        Method               Mean       95% CL Mean        Std Dev      95% CL Std Dev

Female                          27.0952     23.7228 30.4677      7.4088      5.6682 10.6988

Male                            29.8387     25.7333 33.9442     11.1925      8.9441 14.9608

Diff (1-2)    Pooled            -2.7435     -8.3378   2.8509      9.8550      8.2457 12.2505

Diff (1-2)    Satterthwaite     -2.7435     -7.9250   2.4381

                   Method           Variances        DF    t Value    Pr > |t|

                   Pooled           Equal            50      -0.98      0.3294

                   Satterthwaite    Unequal      49.989      -1.06      0.2927

                                      Equality of Variances

                       Method      Num DF    Den DF    F Value    Pr > F

                        Folded F        30        20       2.28    0.0457

Explanation / Answer

b. What is the test statistic for the two-sample t-test? Give the actual number.


-0.98 for pooled
-1.06 for satterthwaite

c. Based on a confidence interval (CI) provided in the output, does mean age differ by gender?

the values are -8.33 and 2.85
as this range contains zero(which signifies no difference) , hence the results are not signficant

Provide the CI and justification for your answer.

d. Based on a p-value provided in the output, does mean age differ by gender? Provide the p-value and justification for your answer.

the p value is 0.3294. considering an alpha of 0.05 , as the p value is not less than 0.05 , hence we fail to reject the null hypothesis and conclude that results are not sigificant


e. Does this data support the professor’s hypothesis that women enter graduate school earlier than men? Why or why not?

as the difference of means is not signficant hence we cant conclude that women enter graudate school earlier than mean.
also as shoewn above , the confidence interval includes both negative and positve values for the difference of means .
Hence this doesnt necesaarily mean that women enter earlier than men in graduate school.

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