Each of the following applies to concepts used in variables sampling. Choose the best response.

a. An important statistic to consider when using a statistical sampling audit plan is the population variability. The population variability is measured by the

(i) Sample mean

(ii) Standard deviation

(iii) Standard error of the sample mean

(iv) Estimated population total minus the actual population total

b. 4 he greater the variability of the items being sampled (as measured by population standard deviation), the

(i) Greater the usefulness of a table of random numbers in selecting a sample

(ii) Larger the sample size required to make reliable statements with a given precision

(iii) Greater should be the level of confidence required when establishing the estimate (iv) More likely that an interval estimate made from sample data will be correct

c. The size of a statistical sample is influenced by the degree of variability in the value of the items being sampled. The standard deviation, a basic measure of variation, is the (i) Average of the absolute differences between the individual values and their mean (ii) Square root of the average of the absolute differences between the individual values and their mean (iii) Average of the squared differences between values and their mean (iv) Square root of the average of the squares of the differences between the individual values and their mean

d. A CPA specifies that a sample shall have a confidence level of 90%. The specified confidence level assures him of (i) A true estimate of the population characteristic being measured (ii) An estimate that is at least 90% correct (iii) A measured precision for his estimate (iv) How likely he can estimate the population characteristic being measured