Give example for each description

a) Increasing confidence level will increase width of confidence interval. This is because the fact that increasing confidence interval will increase value of z(α/2), which will increase the size of standard error (z*s/√n).

b) Increasing sample size will decrease width of confidence interval. This is because the fact that increasing sample size will decrease size of standard error, as square root of sample size is in denominator of standard error term.

c) Increasing original sample statistic will increase midpoint of confidence interval. Suppose that other parameters do not change, width of interval would be unaffected. Size of standard error would be unchanged, only midpoint would change.