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.

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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. 
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 

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d. Confirm test results in part (c) using JASP. Note: All JASP input files and output 
tables should be provided

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Confirm test results in part (c) using JASP.

Note: All JASP input files and output 
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