Discussion Questions

Some psychologists do not consider nominal scales a form of measurement. Any ideas why?

Most psychological measurement is ordinal in nature. Why?

Discuss the types of distributions of data you would expect for the following:

1. IQ test scores from all pupils enrolled in Illinois schools
2. IQ test scores from all pupils enrolled in Bayonne, New Jersey, schools
3. test scores from a very difficult test
4. a series of 1,000 rolls of the die
5. college professors' salaries in a university department in which all of the professors have tenure and have been teaching for more than 20 years
6. test scores from a very easy test.

You are the union negotiator for a company that has a number of very highly paid workers who have been with the company for a very long time. You are trying to negotiate a substantial raise for next year. Which statistic would you want to use to summarize the average salary of your workers, the mean or median? Why?

List examples of nominal, ordinal, interval, and ratio from your everyday experience. Now list them for each of the following: rankings from a gymnastic meet, height, weight, blood type, major league baseball standings, page numbers for this book, your test grades in this course, your college grade point average (GPA), IQ scores, and personality test scores.

As a follow-up to the discussion in the chapter's Everyday Psychometrics section on graphing data, find graphs published in newspapers or magazines. Do these graphs aid in interpreting the data or serve to misrepresent the data?

As a follow-up to the discussion in this chapter's Everyday Psychometrics section, what are some examples of psychological traits that you would not expect to be normally distributed, such as intelligence test scores of university students? Why in each case of a normal distribution presented in this section do the researchers make a special point of stating that the scale under investigation yielded something close to a normal distribution? What are the advantages of knowing that a distribution of a particular trait is normally distributed?