1. Paul uses the stratified random sampling technique of categorization for his research project. He first divides the country into 15 regions; then for each region, he categorizes the population into three age groups; young, adults, and elderly. Finally, he divides these categories into males and females. The number of cells or strata the sampling plan entails is closest to:

A. 20.

B. 45.

C. 90.

2. A researcher is unsure of the underlying population distribution and wants to increase the reliability of the parameter estimates. Which of the following is *least likely* to achieve her objective?

A. Increase in the sample size.

B. Use of point estimates rather than confidence intervals.

C. Use of the t-distribution rather than the normal distribution to establish confidence intervals.

3. Which of the following would result in the t-distribution to approach a standard normal distribution?

A. Increase in degrees of freedom

B. Increase in standard deviation

C. Greater probability in the tails.

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