A researcher takes a simple random sample of 83 homes in a city and finds that the mean square footage is 1628 with a standard deviation of 243 square feet. Which interval is the 90% confidence interval for the mean square footage of all the homes in that city?

ANSWER:

(1584 ft2, 1672 ft2)

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling