The manager of a large company is interested in the commute…

The manager of a large company is interested in the commute times of her employees. She randomly selects 32 employees and finds an average commute time of 25 minutes, with a standard deviation of 5 minutes. (When needed, round to 3 decimals.)   a. What is the point estimate of the population mean commute time? [a] b. Construct a 90% confidence interval for the population mean commute time for this company’s employees (input your interval as “(a, b)”, where a is the lower limit and b is the upper limit of the interval) [b] c. Interpret the interval from part a (write out a sentence and be specific): We are 90% confident that [c]

A local news station is interested in the proportion of loca…

A local news station is interested in the proportion of local residents that regularly get their news source from them rather than on the internet. A researcher randomly selects 170 residents, and found that 45 use the local news station for their news source. (Round to 3 decimal places.)   a. Calculate a 99% confidence interval for the proportion of all local residents that use the local news station for their news source (input your interval as “(a, b)”, where a is the lower limit and b is the upper limit of the interval) [a] b. Interpret the interval from part a (write out a sentence and be specific): We are 95% confident that [b] c. How many local residents need to be sampled in order to estimate the proportion to within 2% with 99% confidence? [c]

Suppose 73% of Americans watch at least 28 hours of TV each…

Suppose 73% of Americans watch at least 28 hours of TV each week. A random sample of 20 Americans was selected. (Round to 3 decimal places.)   a. Find the probability that exactly 18 of those sampled watch at least 28 hours of TV each week. [a] b. Find the probability that more than 17 of those sampled watch at least 28 hours of TV each week. [b] c. Find the expected number of Americans that watch at least 28 hours of TV each week. [c]