(a) In a normal distribution, 68% of the area under the curve is within one standard deviation of the mean.
(b) Given that a normal distribution has a mean of 50 and standard deviation of 5. The median is also 50.
(c) If the variance from a set of data is zero, then all of the data values must be identical.
(d) A 95% confidence interval is wider than and 99% confidence interval of the same parameter.
(e) It is easier to reject the null hypothesis if we have a smaller significance level.
