Mathematics Homework Help

1. Suppose you take a simple random sample from a population known to be normally distributed, and the value of the population standard deviation, ?, is known. Your sample size is n = 10. Which critical value below should be used to find the 90% confidence interval for the population mean?

1.645

1.81

1.83
1.96

7. Data was collected on physical characteristics of Division I starting football players in the 1988 football season. It was reported that the mean weight of all starters on Division I teams in 1988 was 105 kg. A random sample of starting players from Division II teams in 1988 resulted in a sample mean weight of 103.3 kg. Is there sufficient evidence to conclude that the mean weight of Division II starters in 1988 is different than 105 kg, the mean weight of Division I starters?

In order to perform this hypothesis test, in addition to having a random sample, what other assumption must be met?a. Population standard deviation is known or n must be greater than or equal to 10.

b. Population standard deviation is known or n must be greater than or equal to 15.

c. Population standard deviation is known or n must be greater than or equal to 30.

d. Population standard deviation is known or n must be less than or equal to 30.