Question 1 A researcher is interested in measuring the memory recall of students. Twenty students were given fifteen minutes to try to memorize a list of 15 phrases. Each student was then asked to list as many of the phrases as he or she could remember both two hours and twenty-four hours later. The number of phrases recalled correctly for each student are shown below. Student 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Two Hours 7 1 9 13 3 0 3 14 0 12 2 2 12 10 2 4 3 11 5 4 Twenty-Four Hours 2 2 4 14 10 9 4 3 1 3 14 4 1 0 11 10 10 12 14 13 a. Calculate the following for each group: i. 20% trimmed mean ii. The interquartile range b. Test the hypothesis that the mean for the memory after two hours is less than 5. Use the 1% level of significance. c. Determine whether there is evidence, at the 5% level of significance, that for all students, the mean number of words recalled after two hours exceeds that recalled after twenty-four hours.
Question 1
A researcher is interested in measuring the memory recall of students. Twenty students were given
fifteen minutes to try to memorize a list of 15 phrases. Each student was then asked to list as many
of the phrases as he or she could remember both two hours and twenty-four hours later. The number
of phrases recalled correctly for each student are shown below.
| Student | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Two Hours | 7 | 1 | 9 | 13 | 3 | 0 | 3 | 14 | 0 | 12 | 2 | 2 | 12 | 10 | 2 | 4 | 3 | 11 | 5 | 4 |
| Twenty-Four Hours |
2 | 2 | 4 | 14 | 10 | 9 | 4 | 3 | 1 | 3 | 14 | 4 | 1 | 0 | 11 | 10 | 10 | 12 | 14 | 13 |
a. Calculate the following for each group:
i. 20% trimmed mean
ii. The
b. Test the hypothesis that the mean for the memory after two hours is less than 5. Use
the 1% level of significance.
c. Determine whether there is evidence, at the 5% level of significance, that for all
students, the mean number of words recalled after two hours exceeds that recalled
after twenty-four hours.
d. Confirm test results in part (c) using JASP. Note: All JASP input files and output
tables should be provided
Question 2
The University of Michigan is interested in determining if the performance of students in
Advanced Statistics differs depending on whether students attend only online classes or only face
to face. The final grades of 15 students who attend classes solely online was obtained as well as a
further 15 students who attend classes face to face. The grades are provided in the table below:
| Online | 86 | 86 | 91 | 68 | 78 | 45 | 93 | 59 | 63 | 75 | 69 | 79 | 82 | 68 | 47 |
| Face to Face | 50 | 80 | 52 | 92 | 90 | 91 | 72 | 76 | 85 | 44 | 50 | 44 | 57 | 93 | 65 |
a. Construct a box and whisker plot for: (i) online classes and (ii) face to face classes.
b. Test, at the 5% significance level, whether there is a difference in the mean grades of
the two class types.
c. Confirm test results in part (b) using JASP. Note: All JASP input files and output
tables should be provided
Question 3
Gaynor Advertising conducted a survey to determine individual’s main source of news as well as
their educational level. 2500 individuals were surveyed and the results are given below:
| Education | Level | ||||
| Source of News |
Primary | Secondary | Graduate | Post Graduate | Total |
| Newspapers | 95 | 200 | 121 | 400 | 816 |
| Television | 136 | 127 | 135 | 211 | 609 |
| Social Media | 155 | 99 | 170 | 146 | 570 |
| Grapevine | 250 | 135 | 95 | 25 | 505 |
| Total | 636 | 561 | 521 | 782 | 2500 |
a. State both the null and alternative hypotheses.
b. Provide the decision rule for making this decision. Use an alpha level of 5%.
c. Show all of the work necessary to calculate the appropriate statistic.
d. What conclusion are you allowed to draw? [2 marks]
e. Would your conclusion change at the 10% level of significance?
f. Confirm test results in part (c) using JASP. Note: All JASP input files and output
tables should be provided
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d. Confirm test results in part (c) using JASP. Note: All JASP input files and output
tables should be provided
by Bartleby Expertd. Confirm test results in part (c) using JASP. Note: All JASP input files and output
tables should be provided
by Bartleby ExpertConfirm test results in part (c) using JASP.
Note: All JASP input files and output
tables should be provided
by Bartleby Expert
