5.1 HW STATS

b) What proportion of those 30-64 years old in the sample have broken up with someone by digital means. Round your answer to two decimal places e.g. 0.12.

.13

A Pew Research study in April and May of 2013 asked single American adults whether they have ever broken up with someone by e-mail, text, or online message. Consider the following 2 × 2 table of counts: a) What proportion of those 18-29 years old in the sample have broken up with someone by digital means. Round your answer to two decimal places e.g. 0.12.

.22

5.1.3 What value should you put in the cell with the question mark in the table so that there is no association between group and outcome? Group A Group B Total Success 10 15 25 Failure 40 ? Total 50

60

Suppose that in a randomized experiment investigating the effect of incentive on whether a person agrees to take a survey, the data are as given in this table. What is an appropriate way to evaluate the effectiveness of the incentive? $5 incentive No incentive Total Took survey 48 7 55 Didn't take survey 12 33 45 Total 60 40 100

Compare 48/60 to 7/40

c. Is there a larger proportion of nappers among those that regularly drink coffee or do

There is a larger proportion of nappers among those who regularly drink coffee, because the graph shows roughly 60% nappers in the regular coffee group compared to roughly 55% nappers in the non-coffee group.

c) Would you say there is preliminary evidence of an association between age and breaking up with someone by digital means?

Yes, since the conditional proportions are quite different.

b. Are there more people that have taken naps in the past 3 days than have not taken naps in the results? Choose the best among the following statements.

Yes, there are more nappers than non-nappers in both the regular coffee group and the non-coffee group; the proportion of the bar that represents nappers is greater than 50%.

A survey of 122 statistics students included a question that asked them if they are a regular coffee drinker and if they took a nap in the past 3 days. Use the results shown in this mosaic plot to answer the questions. a. Were there more regular coffee drinkers than non-coffee drinkers in the results?

Yes, there are more regular coffee drinkers than non-coffee drinkers in the sample because the width of the bar for coffee drinkers is wider than the width of the bar for non-coffee drinkers.