More carry-on bags for passengers on a flight can delay the loading and un-loading of passengers. Suppose a random sample of 600 passengers for an airline indicated that 172 had more than one carry-on bag. Calculate and interpret the 80% confidence interval estimate for the true proportion of passengers for this airline that have more than one carry-on bag.

A Gallup poll of 1487 adults showed that 43% of the respondents have Facebook pages.  Construct a 95% confidence interval for the proportion of adults who have a Facebook page.

A recent survey showed that 42% of US employers were likely to require higher employee contributions for health care coverage. Suppose the survey was based on a sample of 500 companies. Find the 99% confidence interval for the proportion of all companies likely to require higher employee contributions for health care coverage. (Round to four decimal places)

In a survey of 1000 households, 800 had cell phones but no landline. Construct a 95% confidence interval for the proportion of all households with a cell phone but no landline.

7) Suppose that in a sample of 5274 customers at a food store, 2468 food shop more than once a week. Find a 98% confidence interval for the population proportion of customers who shop more than once a week. Interpret your answer.

Car and Driver Magazine tested a random sample of 9 hybrid cars and found their MPG to be 42, 51, 39, 44, 52, 48, 51, 44, and 47. Construct a 95% confidence interval for the population variance.

In a sample of 400 Canadians, 220 say they would rather retire in the US than in Canada. Calculate the 95% confidence interval for the true proportion of Canadians who would rather retire in the US.

The National Research center conducted a survey of 1000 people to learn about their major international concern.  The survey results showed that 760 of the respondents indicated computer cyber attacks is their major international concern.  Develop a 94% confidence interval for the population proportion of adults who think computer cyber attacks is their major international concern.