Suppose babies born in a large Hospital have a mean weight of 4088 in a variance of 5569. if 128 babies are sample that a random from the hospital what is the probability that the mean weight of the sample babies would differ from the population mean by less than 41 grams round your answer to four decimal places?

Answer 1

If I recall correctly,
sd = √5569 = appr 74.626

so we want between 4088+41 and 4088-41
that is , between 4129 and 4047

Using my favourite webpage for this stuff,
http://davidmlane.com/hyperstat/z_table.html
and entering the above data, I got a probability of .4173

So for 128 that would be 53 babies