A simple random sample of 70 items resulted in a sample mean of90. The population standard deviation is
σ = 5.
(a)
Compute the 95% confidence interval for the population mean.(Round your answers to two decimal places.)
to
(b)
Assume that the same sample mean was obtained from a sample of140 items. Provide a 95% confidence interval for the populationmean. (Round your answers to two decimal places.)
to
(c)
What is the effect of a larger sample size on the intervalestimate?
A larger sample size provides a smaller margin of error
.A larger sample size does not change the margin oferror.   Â
A larger sample size provides a larger margin of error.
