Question

The mean age for all Foothill College students for a recent Fall term was 33.2. The population standard deviation has been pretty consistent at 15. Suppose that twenty-five Winter students were randomly selected. The mean age for the sample was 30.4. We are interested in the true mean age for Winter Foothill College students. Let X = the age of a Winter Foothill College student.

A. Construct a 95% Confidence Interval for the true mean age of Winter Foothill College students by working out then answering the exercise.

Fill in the blanks on the graph with the areas, upper and lower limits of the confidence interval, and the sample mean. (Round your answers to three decimal places.)

B. Construct a 95% Confidence Interval for the true mean age of Winter Foothill College students by working out then answering the exercise.

Identify the following specifications. (Round your answers to two decimal places.)

upper limit =

lower limit =

error bound =

C. Construct a 95% Confidence Interval for the true mean age of Winter Foothill College students by working out then answering the exercise.

How much area is in both tails (combined)? (Enter an exact number as an integer, fraction, or decimal.)

α =

Answer 1

Answer:

a)

b)

upper limit = 36.28

lower limit = 24.52

error bound = 5.8799 = 5.88

c)

The area is in both tails (combined) = α = 5% = 0.05