Chapter 1 A teacher wishes to know whether the males in his/her class have more favorable attitudes toward gun control than do the females. All students in the class are given a questionnaire about gun control and the mean responses of the males and the females are compared. Is this an example of descriptive or inferential statistics? A medical researcher is testing the effectiveness of a new drug for treating Parkinson's disease. Ten subjects with the disease are given the new drug and 10 are given a placebo. Improvement in symptomology is measured. What would be the roles of descriptive and inferential statistics in the analysis of these data? What are the advantages and disadvantages of graphical as opposed to numerical approaches to descriptive statistics? Distinguish between random and stratified sampling? A study is conducted to determine whether people learn better with spaced or massed practice. Subjects volunteer from an introductory psychology class. The first 10 subjects who volunteer are assigned to the massed-practice condition; the next 10 are assigned to the spaced-practice condition. Discuss the consequences and seriousness of each of the following 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. In general, which type of non-random sampling is more serious? Define independent and dependent variables. Categorize the following variables as being qualitative or quantitative: Response time Rating of job satisfaction Favorite color Occupation aspired to Number of words remembered Specify the level of measurement used for the items in Question 7. Categorize the variables in Question 7 as being continuous or discrete. Are Greek letters used for statistics or for parameters? When would the mean score of a class on a final exam be considered a statistic? When would it be considered a parameter? An experiment is conducted to examine the effect of punishment on learning speed in rats. What are the independent and dependent variables? For the numbers 1, 2, 4, 8 Compute: ΣX ΣX2 (ΣX) 2 ΣX = 7 and ΣX² = 21. A new variable Y is created by multiplying each X by 3. What are ΣY and ΣY² equal to ? Selected Answers