Question

1. Over 9 months, a random sample of 100 women were asked to record their average menstrual cycle length (in days).

The sample average was 28.86 days, with a sample standard deviation of 4.24 days.

(a) Calculate the lower bound for the 90% confidence interval for the true average menstrual cycle length.

(b) Calculate the upper bound for the 90% confidence interval for the true average menstrual cycle length.

(c) Interpret the confidence interval found in (a,b) in terms of the problem.

(d) A researcher hypothesized that womens menstrual cycles are typically the same length as a lunar month - 29.5

days. Does your interval from (a,b) support this hypothesis?

(e) Are the assumptions for a confident interval met for this problem?

PLEASE SHOW HOW YOU DID IT AND DON'T JUST SIMPLY DO IT, THANK YOU. WHERE DO THE NUMBERS COME FROM, THANKS <3

Answer 1

  

  

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c) a) We are 90% confident that the mean is atleast 28.31

b) We are 90% confident that the mean is not greater than 29.41

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d) a) This 90% Lower bound is atleast 28.31 so, 29.5 is the part of lower bound

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e) Yes, Random sampling and that distribution can be assumed to be normal because sample size is greater than 30