A smart phone manufacturer is interested in constructing a 95% confidence interval for the proportion of smart phones that break before the warranty expires. 90 of the 1695 randomly selected smart phones broke before the warranty expired. a.  With 95% confidence the proportion of all smart phones that break before the warranty expires is between  and . b.  If many groups of 1695 randomly selected smart phones are selected, then a different confidence interval would be produced for each group. About  percent of these confidence intervals will contain the true population proportion of all smart phones that break before the warranty expires and about  percent will not contain the true population proportion.

A survey of 360 college seniors found that 305 wish they had spent more time studying. Find a 94% confidence interval for the true proportion p of those who wish they had spent more time studying.

The New York Times conducted a nationwide poll of 1048 randomly selected 13- to 17-year-olds. to estimate the proportion of 13- to 17-year-olds who have a television in their room. We can consider the sample to be a simple random sample. Of these 1048 teenagers, 692 had a television in their room. Give a 95% confidence interval for the proportion of all people in this age group who had a TV in their room at the time of the poll, and interpret what your interval means in context. State: Plan:  Do: Conclude:

In a certain state, a survey of 500 workers showed that 38% belonged to a union.  Find the 93% confidence interval for the overall proportion of workers who belong to a union

Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 399 drivers and find that 285 claim to always buckle up. Construct a 83% confidence interval for the population proportion that claim to always buckle up. Use interval notation, for example, [1,5]

A smart phone manufacturer is interested in constructing a 90% confidence interval for the proportion of smart phones that break before the warranty expires. 85 of the 1594 randomly selected smart phones broke before the warranty expired. Round answers to 4 decimal places where possible.a. With 90% confidence the proportion of all smart phones that break before the warranty expires is between and .b. If many groups of 1594 randomly selected smart phones are selected, then a different confidence interval would be produced for each group. About percent of these confidence intervals will contain the true population proportion of all smart phones that break before the warranty expires and about percent will not contain the true population proportion.

When 258 college students are randomly selected and surveyed, it is found that 106 own a car. Find a 99% confidence interval for the true proportion of all college students who own a car.

8.2  Question 3).  According to the February 2008 Federal Trade Commission report on consumer fraud and identity theft, Arkansas had 1,601 complaints of identity theft out of 3,482 consumer complaints ("Consumer fraud and," 2008). Calculate a 90% confidence interval for the proportion of identity theft in Arkansas.

Out of a sample of 760 people, 367 own their homes. Construct a 95% confidence interval for the population mean of people in the world that own their homes. A CL

A random sample of 1000 NAU students in Flagstaff found 470 NAU students who drink coffee daily. Find a 95% confidence interval for the true percent of NAU students in Flagstaff who drink coffee daily. Express your results to the nearest hundredth of a percent.  Answer ___to____%