Question

A random sample of the birth weights of 186 babies has a mean of 3103 g and a standard deviation of 668g.?
Construct a 90% confidence interval estimate of the mean birth weight for all such babies. What is the confidence interval estimate of the mean birth weight for all such babies?

Answer 1

90% confident that the population mean birth weight is between: 3022.43 grams and 3183.57 grams.

{ 3103 - [1.645* 668/(186)^(1/2)] . 3103 + [1.645* 668/(186)^(1/2]}

I used formulas from the link below.

http://myweb.astate.edu/sbounds/Statistics_AP/5%20Week%205/ELAD_6773_WEEK_05_READING_02_IllowskyCh8ConfidenceIntervals.pdf