Exercises
Prerequisites
• All material presented in Chapter: “Introduction”
1. A teacher wishes to know whether the males in his/her class have more conservative attitudes than the females. A questionnaire is distributed assessing attitudes and the males and the females are compared. Is this an example of descriptive or inferential statistics?
2. A cognitive psychologist is interested in comparing two ways of presenting stimuli on sub- sequent memory. Twelve subjects are presented with each method and a memory test is given. What would be the roles of descriptive and inferential statistics in the analysis of these data?
3. If you are told only that you scored in the 80th percentile, do you know from that description exactly how it was calculated? Explain.
4. A study is conducted to determine whether people learn better with spaced or massed practice. Subjects volunteer from an introductory psychology class. At the beginning of the semester 12 subjects volunteer and are assigned to the massed-practice condition. At the end of the semester 12 subjects volunteer and are assigned to the spaced-practice condition. This experiment involves two kinds of non-random sampling: (1) Subjects are not randomly sampled from some specified population and (2) subjects are not randomly assigned to conditions. Which of the problems relates to the generality of the results? Which of the problems relates to the validity of the results? Which problem is more serious?
5. Give an example of an independent and a dependent variable.
6. Categorize the following variables as being qualitative or quantitative:
Rating of the quality of a movie on a 7-point scale
Age
Country you were born in
Favorite Color
Time to respond to a question
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