Fill This Form To Receive Instant Help
Homework answers / question archive / ST 352 R Tutorial Assignment 5 Analysis of Categorical Data 20 points Problem: You participated in a “memory game” activity
ST 352
R Tutorial Assignment 5
Analysis of Categorical Data
20 points
Problem: You participated in a “memory game” activity. In this problem, you will answer this question of interest: “Is there an association between the time of day when the activity was performed and how many items were remembered?” Use the memorygame data set posted on Canvas to answer this question of interest. Note: the number of items remembered is categorized into two groups. The data set will contain two columns: column 1 is the time of day the activity was performed (“time”) and column 2 is whether or not at least 60% of the items were remembered (“pctremember”):
• time (time of day you performed the activity: “early” or “late”)
• pctremember (“yes” = remembered at least 60% of the items, “no” = remembered less than 60% of the items)
1. (2 points) Construct a table of counts and a table of proportions (with appropriate comparison proportions to answer the question of interest). Use R to obtain these tables, but do NOT copy and paste those tables into your assignment. Instead, use the tables from R to construct your own table where you include both the counts and proportions (or percentages) in the same table.
Table of Counts

evening 
morning 
<= 60% remembered 
14 
31 
At least 60% remembered 
14 
21 
Table of Proportions

evening 
morning 
<= 60% remembered 
0.5000 
0.5962 
At least 60% remembered 
0.5000 
0.4038 
2. (2 points) Based on the proportions in #1, does it appear that the proportion remembering at least 60% of the items is different between those who performed the activity in the morning and those who performed the activity in the evening? Briefly explain.
3. (3 points) State the null and alternative hypotheses in statistical notation. Define the notation in the context of the problem.
4. (2 points) Report the expected counts for all cells in the table. Are the expected counts “large enough” for conclusions from the chisquare test to be valid to the population? Briefly explain.
5. (2 points) Report the chisquare statistic with degrees of freedom and the pvalue here.
6. (4 points) Answer the question of interest in the context of the problem.
7. (5 points) Report and interpret the 95% confidence interval for the difference in the population proportion remembering at least 60% of the items between those who did the activity in the morning (labeled “early” in the data set) and those who did the activity in the evening (labeled “late” in the data set): (p_{early} – p_{late})
Already member? Sign In