Answer Happy

A simple random sample of size n is drawn from a population that
is normally distributed. The sample mean is found to be
113 and the sample standard deviation, s, is found to be
15.
Find the following confidence intervals with a calculator and
round to one decimal place using this to find the margin of error,
E.
a. Construct a 90% confidence interval for µ if the sample size,
n, is 14
Confidence interval = ( , ), E = ( )
b. Construct a 90% confidence interval for µ if the sample size,
n, is 15
Confidence interval = ( , ), E = ( )
c. How does increasing the sample size affect the margin of
error, E?
Increases/Decreases margin of error
d. Construct a 95% confidence interval for µ if the sample
size, n, is 14
Confidence interval = ( , ), E = ( )
e. Compare to results from part a, how does increasing level of
confidence affect margin of error, E?
Increases/Decreases margin of error