Question

The mean age at which men marry in the United States is 24.8 years, with a standard deviation of 2.5 years. A simple random sample of 90 men is taken What is the name of the theory that allows us to use a normal distribution to approximate the sampling distribution? a. b. Compute the standard error of the mean for this sample of 90 men. Round your answer to three decimal places. What is the probability that the sample mean with be within 0.25 years of the population mean? c. d. What is the probability that the sample mean with be within 0.5 years of the population mean? Researchers would like to achieve a 0.95 probability that their sample mean will be within 0.5 years of the population mean. What will need to happen to their sample size (i.e. will it need to increase or decrease)? e.

Answer 1

DATE Solution Criven hat meane u s 24:8 y ears stanalard devia han 25 years mn O. allhie ca use thhe centrel tinit theore eistnibu ion to approximate the sam the sample ea s Same a mean 2 s2.5 6x = o.263 sanmple nean wuith be within 25 years 아 epuulation meam) 25.05-24.8 o 26 0.263

DATE 0. 263 o 263 tas probabsly that the sample mean uith be wuthia o.2s years of H popula tio reani 0.6 S78 O 263 o26 3 .9713 0287 ー ーー0.qlt 2 6 : th pobablity that the sample mea with be within 0 year ot the rgin of eo.S Here given tat, ma

PAGE No. DATE 2 2 16.04 17 Rssearchem aalal like to achieve ill be within 5 year sf the