The approval rating of the President is the percentage of people surveyed who believe the President is doing a good job. The histogram in Fig. 90 displays President Obama€™s daily approval ratings in 2009.
Fig. 90

a. Describe the shape of the distribution. What does this mean in this situation?
b. The approval rating 54% is at the 50th percentile, which is a measure of the center. The center of a unimodal distribution tends to be a typical value. Is that true for this situation? Explain.
c. Figures 91 and 92 display histograms of President Obama€™s approval ratings for the first half of 2009 and the second half of 2009, respectively. Is the 50th percentile for the first half of 2009 less than, greater than, or approximately equal to the 50th percentile for the second half of 2009? What does that mean in this situation?
Fig. 91

Fig. 92

d. Compare the spreads of the distributions for the two halves of 2009.
e. How do the distributions for the two halves of 2009 explain why the distribution for all of 2009 is bimodal?

Transcribed Image Text:

Approval Rating 2009 70 60 e 50 40 30 20 10 43 47 5 55 59 63 67 71 Percent Approval Ratings First Half of 2009 70 60 50 40 30 20 10 Th 43 47 51 55 59 63 6771 Percent Approval Ratings Second Half of 2009 70 60 S 50 40 30 20 10 43 47 51 55 59 63 6771 Percent