Nutshell

Much like an artist needs paint to paint a picture, a researcher needs measures of central tendency and variability to describe a dataset concisely. The purpose of a measure of central tendency is to provide one number that describes a large set of data. There are three measures of central tendency: mean, median and mode. It has been discussed and examined how they are calculated. Although the mean, median, and mode are essential in helping describe a dataset concisely, they do not provide certain information that is often essential in learning about a dataset. The above section, we begin by examining what we mean by variability and why it is critical to any research study. We then examine three specific measures of variability and how to calculate and interpret each one.

Knowledge Problem Solving A researcher surveyed 10 undergraduate psychology majors about their study behaviors. The following is a list of the number of hours they spent studying on the weekend: 6 5 3 4 9 7 3 7 B 3 1. Calculate the mean. 2. Calculate the median. 3. Calculate the mode. 4. Calculate the range. 5. Calculate the variance. 6. Calculate the standard deviation. Identication 7. The value of one score in a dataset is changed from 20 to 30. Which measure(s] of central tendency is (are) certain to change? 3. A survey asks whether people think a politician is innocent or guilty of embezzlement Which would be the best measure of central tendency to describe this dataset? 9. The value of one score in a dataset is changed from 20 to 30. Which measure{s] of variability istare] certain to be changed? 10. Which measure of variability would be more affected by an outlier: the range or the standard deviation