Answering Questions about Population Characteristics

Abstract

This chapter demonstrates methods for using estimates of population characteristics to provide yes—no answers to questions about the population. This form of statistical inference, called hypothesis testing, uses a sample of data to draw conclusions about its parent population. This chapter demonstrates how to use SPSS to test hypotheses about characteristics of a single population such as the mean, median, proportion, or mean of paired measurements. For example, we might test whether:

• the average IQ score for a group of students is equal to 100;

• the proportion of minority firefighter applicants is 26%, the same as the general population;

• the median speed of automobiles on the highway is 55 mph;

• reading scores for students exposed to a particular instruction program change over time.