1'. Does stratication help in estimating the average family income? From a simple random sample of size 400, estimate the average income and also the standard error of your estimate. Form a 95% condence interval. Next, allocate the 400 observations proportionally to the four regions and estimate the average income from the stratied sample. Estimate the standard error and form a 95% con- dence interval. Compare your results to the results of the simple random sample