1. In a sample of 25 new cars, we find that the mean mileage per gallon (mpg) is 96.52 with the standard deviation of 10.70.

What is the 90% confidence interval for the population mean.

Assume that mpgs follow a normal distribution.

2. In a sample of 25 new cars, we find that the mean mileage per gallon (mpg) is 96.52. p=0.28

Construct 99% interval for the population proportion of all new cars that have the mpg over 100.

3. A trade group predicts that back-to-school spending will average

$606.40 per family this year. A different economic model is needed if the prediction is wrong.

Specify the Ho and Ha.

4. a) A television research analyst wishes to test a claim that more than 50% of the households will tune in for a TV episode.

Write the appropriate Ho and Ha hypothesis.

b) b) A television research analyst wishes to test a claim that more than 50% of the households will tune in for a TV episode.

Write the appropriate Ho and Ha hypothesis.