A survey35 asked a random sample of n = 2752 US adults whether they had visited a public library in the last 12 months. The results for males and females are shown in Table 6.5.   Have you visited a public library in the last year?   Yes No Total Females 726 697 1423 Males 505 824 1329 Total 1231 1521 2752   (a)  Find p^f and p^m, the sample proportions who have visited a public library in the last 12 months, for females and males respectively. What is the difference in sample proportions p^f−p^m?       (b)  Find a 95% confidence interval for the difference in population proportions pf − pm.       (c)  Can we conclude from the confidence interval that there is a difference in proportions? If so, are males or females more likely to visit the public library?

2 3 4 P 5 D 6 7 8 The data shown here were collected via a phone survey in 2010 of 625 cell phones users of age 12 to 17 by the Pew Research Foundation. If we select a person at random from this sample: type your answer..... Number of text messages sent or received on a typical day 0 1-10 11-20 21-50 type your answer.... 51-100 101+ type your answer... % of teen cell phone users Round your answers to the nearest hundredth, O.XX. a. What is the probability that the person responded that s/he texted more than 100 times per day? c. What is the probability that the person did not respond that she never texts? 2% 22% 11% 18% 18% b. What is the probability that the person responded that s/he texted between 21 and 100 times on a typical day? ?

Pavan

Hospitals In a study of births in New York State, data were collected from four hospitals coded as follows: (1) Albany Medical Center; (1438) Bellevue Hospital Center; (66) Olean General Hospital; (413) Strong Memorial Hospital. Does it make sense to calculate the average (mean) of the numbers 1, 1438, 66, and 413?

To evaluate the current status of physical activity in university students at BU, a student in Business surveyed students from their class by randomly selecting 12 rows and collecting data one 2 people from each of the selected rows. The question asked: "How many hours per week do you exercise?" What is the sample? O Students in Business at BU. O The 24 surveyed students. O Students at BU Everyone at BU. ONone of the above.