If the random variable X is exponentially distributed,then the mean of X will be:

A) greater than the median.
B) less than the median.
C) equal to the median.
D) Cannot tell; the answer depends on what λ is.

If two groups of numbers have the same mean, then

A) their standard deviations must also be equal.
B) their medians must also be equal.
C) their modes must also be equal.
D) other measures of location need not be the same.