Ch 11 Q 4. I got this question wrong on my homework. I don't have a TI 84 calculator. The correct answers are attach and I don't know how to get those answers.

c) What is the confidence interval using the given population standard deviation? Select the correct choice below and fill in the answer boxes within your choice. (Round to two decimal places as needed.) O A. The new confidence interval ( , ) is narrower than the interval from part a. "B. The new confidence interval ( 29.96 , 35.88 ) is wider than the interval from part a.A survey of 25 randomly selected customers found the ages shown (in years). The mean is 32.92 years and the standard deviation is 8.49 42 29 32 28 40 years. 38 31 44 24 29 a) Construct a 90% confidence interval for the mean age of all customers, assuming that the assumptions and conditions for the confidence 21 18 20 42 39 interval have been met. 37 23 33 36 42 b) How large is the margin of error? 35 39 18 46 37 c) How would the confidence interval change if you had assumed that the standard deviation was known to be 9.0 years? a) What is the confidence interval? ( 30.01 , 35.83) (Round to two decimal places as needed.) b) What is the margin of error? The margin of error is 2.91 . (Round to two decimal places as needed.)