Answer the following questions by checking either True or False.
(a) All other factors remaining the same, a 90% confidence interval is more narrow than a 95% confidence interval.
(b) All other factors remaining the same, increasing our sample size, n, will decrease the width of our confidence interval.
(c) All other factors remaining the same, a smaller standard deviation will increase the width of our confidence interbal.
(d) A confidence interval for a population mean is always symmetric and centered around the sample mean.