Exam 3: Correlation and Prediction

A researcher studying the relation of length of court trials to length of time for juries to come to a decision reports the following results for the first four trials considered. M = 8.75 SD = 6.83 M = 7.5 SD = 2.96 r = .91 a. Give the Z score prediction formula for predicting length of jury deliberation from length of trial. b. Predict the hours of deliberation for a jury where the trial lasted for 10 days. c. Explain what you have done to a person who is familiar with correlation but not with regression.

In multiple regression, the overall correlation between the criterion variable and all the predictor variables is called the:

A person's predicted Z score on the criterion variable is found by multiplying that person's Z score on the predictor variable by a particular number called a:

If the true pattern of association between variables is curvilinear, figuring the correlation in the usual way could result in little or no correlation. (True or False)

A researcher studying the relation of similarity to attraction reported the following results: M = 3.25 SD = 1.92 M = 6 SD = 2.55 r = .36 a. Give the Z score prediction formula for predicting attraction from similarity. b. Predict the attraction to a person for whom the similarity is rated as a 5. c. Explain what you have done to a person who is familiar with correlation but not with regression.

Figure the predicted Z score on the criterion variable (Y)for the following situation: The correlation coefficient is .50 and the Z score for the predictor variable (X)is 1.20.

What is meant by the phrase strength of the correlation?

A study found that absenteeism from work had a negative linear correlation with job satisfaction. This means that:

Comparisons of the strength of linear correlation are considered most accurate in terms of the __________.

__________ is the number you multiply by the Z score of the predictor variable to obtain the predicted Z score on the criterion variable.

You take the sum of the cross-products of Z scores and divide it by the number of people in the study. You are figuring:

A study finds that the longer a book, the less willing children are to read it. This relation between book length and children's interest is an example of a(n)__________ correlation.

The average of the cross-products of Z scores is:

An organizational specialist administered questionnaires to three new employees, assessing psychological rigidity and adjustment to their new job. The scores are as follows. M = 5.67 SD = 1.25 M = 13.33 SD = 5.44 r = -.92 a. Give the Z score prediction formula for predicting adjustment to retirement from scores on the rigidity scale. b. Predict the adjustment to a new job for a person who scores 8 on the rigidity scale. c. Explain what you have done to a person who is familiar with correlation but not with regression.

A perfect linear correlation means that all the dots fall exactly on the straight line. (True or False)

It is a good idea to make a scatter diagram before figuring the correlation coefficient. This is because:

Suppose you are making predictions about people's poetry ability based on scores on a general writing-ability test. However, you also happen to have information about their creativity scores when making your predictions. What is it called when you make a prediction using both pieces of information?

In a true experiment, participants are __________ a particular level of a variable and then are measured on another variable.

Researchers say that a correlation is significant if:

A correlation describes the relationship between two: