13.
Sampling distribution of mean is very close to the standard normal distribution when:

15.
Under. . . . . . . ., only the first unit of the sample is selected at random and the remaining units are selected at fixed intervals.

16.
The formula to determine the number of classes given by Sturge's Rule is which one of the following?
Where: K = Number of classes; N = Total number of observations
Logarithm of the total number of observations

18.
Sampling is simply the process of learning about the 'population' on the basis of a part of the universe or population called . . . . . . . . drawn from it.

19.
In regression analysis, the variable that is used to explain the change in the outcome of an experiment, or some natural process, is called: