Chapter 8.3, Problem 66E

a)

To determine

To explain whether the conditions for calculating a confidence interval for the population mean.

Answer to Problem 66E

The condition of random sample and independent is not met.

Explanation of Solution

Given:

The population of all U.S. president.

All the individuals in the population of U.S. presidents were included in the sample so it could not be random sample. Hence the condition of random sample not met.

The sample should be less than 10% of the population. Here, the sample of U.S. presidents are not less than 10% of the population of all U.S. president. Hence, this condition not met.

The sample size will be greater than 30 as there are more than 30 U.S. presidents. Therefore, larger sample size condition satisfied.

b)

To determine

To explain whether the conditions for calculating a confidence interval for the population mean.

Answer to Problem 66E

The conditionof large sample is not met.

Explanation of Solution

Given:

The sample size n = 25

The population of all students

The students were randomly selected so it is a random sample. Hence the condition of random sample met.

The sample should be less than 10% of the population. Here, the sample of 25 students areless than 10% of the population of all students. Hence, this conditionmet.

The sample size 25 is less than 30. Therefore, larger sample size condition is not satisfied.