Fewer young people are driving. In 1983, 87% of 19 -year-olds had a driver's license. Twenty-five years later that percentage had dropped to 75% (University of Michigan Transportation Research Institute website, April 7, 2012). Suppose these results are based on a random sample of 1200  19-year-olds in 1983 and again in 2008. a. At 95% confidence, what is the margin of error and the interval estimate of the number of 19 -year-old drivers in 1983? Round your intermediate answers to four decimal places. Margin of error (four decimal places) Interval estimate (to four decimal places) to b. At 95% confidence, what is the margin of error and the interval estimate of the number of -year-old drivers in 2008? Round your answers to four decimal places. Margin of error Interval estimate to

According to recent data by the American Marketing​ Association, 76.5​%of people in the​ 18-24 age group used social media in 2017. You want to find out what the social media proportion is among your classmates who are all between 18 and 24 years old. Suppose you obtain a random sample of 229 students and find that 202 students in this sample are active social media users. Complete parts a through c below.   a. Construct a 99​% confidence interval to estimate the actual proportion of social media users. A 99​% confidence interval to estimate the actual proportion has a lower limit of------ and an upper limit of------- ​(Round to three decimal places as​ needed.) b. What is the margin of error for this​ sample? c. Is there evidence that this proportion matches that of the overall population based on the​ sample?

The 2006 Statistical Abstract of the United States reports on a survey that asked a national sample of 80,000 American households about pet ownership. Suppose (for now) that one-third of all American households own a pet cat. Still supposing that one-third of all American households own a pet cat, between what two values do you expect 95% of all sample proportions to fall?

You want to estimate the average difference in the number of complaints filed by women at work and the number of complaints filed by men at work.  You took an SRS of 7 businesses and collected the following data for number of complaints in a year: men 1 3 2 4 6 3 5 women 8 7 6 3 5 12 15   Create a 90% confidence interval for the average difference in the number of complaints filed by women at work and the number of complaints filed by men at work (in a year).  You must do this using table C.  If this is a 2 sample interval, be sure to specify who is population 1 and who is population 2.  If this is a matched pairs interval, be sure to state the order you subtracted your data.  Once you create your interval, give a sentence explaining the meaning of the interval (what the numbers in the interval mean, NOT the meaning of 95%) in context of this problem.  Round to any appropriate number of decimals.

A survey of 32,782 adults in 2004 indicated that 24.6% of adults were current smokers. A similar study conducted in 1995 of 40,000 adults indicated that 29.7% were current smokers. a. Find and interpret a point estimate of the difference between the proportion of current smokers in 1995, and the proportion of current smokers in 2004. b. A 95% confidence interval for the true difference is (-0.058,-0.045). Interpret. c. What assumptions must you make for the confidence interval i part b to be valid? (…) a. Find a point estimate of the difference between the proportion of current smokers in 1995 and the proportion of current smokers in 2004. (Round to three decimal places as needed.)

A survey of 41 students in grades 4 through 12 found 63% have classroom Wi-Fi access. Find the 99% confidence interval of the population proportion. .