Explanation : The parameters of the sampling distribution
are related to the parameters of the distribution
of data. The means of the two distributions
are equal to the same value. This will always
be the case for any unbiased estimate. An
unbiased estimate is equal to the population’s
parameter, on the average. This is reflected in
the sampling distribution by having the mean
equal to the parameter that is being estimated
(i.e., mean of the distribution of data).
The variances and standard deviations of the
sampling distribution and distribution of data
are related, but not equal to the same value.
The sampling distribution is less dispersed
than is the distribution of data. The reason for
this is that the impact of extreme data values
in a sample is offset by less extreme data
values. Thus, estimates of the mean have less
variation than do the data. How much less,
depends on the number of observations in the
sample. The greater the number of
observations, the less variable the estimates.
To emphasize the difference in dispersion
between the sampling distribution and the
distribution of data, the standard deviation of
the sampling distribution is usually called the
standard error.