CSSBB Sample Practice Questions

Deming called the technique of studying a sample to gain understanding of the distribution of a population an “enumerative study.” His main objection to these studies was:

• AA. they are too difficult to perform correctly
• BB. they require extensive use of computers
• CC. they assume a stable distribution
• DD. random samples are expensive to obtain
• EE. these studies have a high probability of Type II error

Samples of size n=36 are randomly selected from a population with mean = 125 and variance 12. Find the variance of the distribution of sample means.

• AA. .333
• BB. .577
• CC. 2
• DD. 3.464
• EE. 12

A population is bimodal. One hundred samples of size 30 are randomly collected and the 100 sample means are calculated. The distribution of these sample means is:

• AA. bimodal
• BB. approximately exponential
• CC. approximately Poisson
• DD. approximately normal
• EE. approximately uniform