Unit 4: Correlation - Practice Quiz

1 Which type of correlation occurs when both variables increase together?

2 Which type of correlation occurs when one variable increases while the other decreases?

3 What does zero correlation indicate?

4 A correlation coefficient of represents which relationship?

5 A correlation coefficient of represents which relationship?

6 What does Pearson's correlation coefficient measure?

7 What symbol is commonly used for the sample Pearson correlation coefficient?

8 What is the possible range of Pearson's correlation coefficient?

9 Which value indicates a stronger correlation?

10 What does the sign of Pearson's show?

11 Which measurement level is generally appropriate for Pearson's correlation?

12 If , how would the relationship usually be described?

13 What does multiple correlation examine?

14 What symbol commonly represents the multiple correlation coefficient?

15 How many predictor variables are required for multiple correlation?

16 What is the usual range of the multiple correlation coefficient ?

17 A multiple correlation of indicates what?

18 What type of data is especially suitable for Spearman's rank-order correlation?

19 What symbol commonly represents Spearman's rank-order correlation?

20 Spearman's rank-order correlation is based mainly on what?

21 A researcher finds that as daily stress increases, sleep quality tends to decrease in a fairly consistent pattern. What type of correlation is most appropriate?

22 The relationship between arousal and performance is low at very low and very high arousal but highest at moderate arousal. Which type of relationship does this illustrate?

23 If two psychological variables have a correlation of , which conclusion is most justified?

24 A scatterplot shows points closely following a downward-sloping straight line. Which description best fits the relationship?

25 A study reports a correlation between study time and examination scores. Which statement is the most appropriate interpretation?

26 What does Pearson's correlation coefficient primarily measure?

27 A sample produces between social anxiety and number of social interactions. Which interpretation is best?

28 If , what proportion of variance is explained by the linear relationship?

29 Which value indicates the strongest linear relationship between two variables?

30 Which situation is most likely to make Pearson's correlation misleading?

31 If every participant's score on one variable is converted from minutes to seconds, what happens to Pearson's ?

32 A researcher obtains from a sample of 20 participants. Which statement is most accurate?

33 What does a multiple correlation coefficient, usually denoted by , describe?

34 A regression model predicts academic performance from conscientiousness, prior achievement, and study hours. What does represent?

35 A multiple correlation coefficient is reported as . What is the corresponding coefficient of determination?

36 Which statement about the multiple correlation coefficient is correct?

37 When a second predictor is added to a multiple regression model, the ordinary will generally:

38 Spearman's rank-order correlation is most appropriate when the variables are:

39 Six students receive the same ordering of ranks for motivation and attendance. What is Spearman's rank correlation likely to be?

40 For six cases, the differences between paired ranks have squared values that sum to . Using , what is ?

41 A researcher observes that stress rises with workload up to a moderate level, but among employees with extremely high workload, stress scores plateau because of emotional disengagement. Which type of association is most appropriate for describing the overall relationship?

42 Variable increases as variable increases, but the increases become progressively smaller. Which statement is most accurate?

43 In a sample, anxiety and performance show a strong positive correlation within low-anxiety participants and a strong negative correlation within high-anxiety participants. The aggregate correlation is close to zero. What is the best interpretation?

44 If every score on is transformed to while is unchanged, what happens to Pearson's correlation?

45 A dataset has Pearson correlation . One observation is deleted, and the new correlation is . Which conclusion is justified?

46 Suppose , , and . What is the least-squares regression slope for predicting from ?

47 A study reports between therapy attendance and symptom improvement. Which statement is most defensible?

48 A scatterplot shows a strong U-shaped relationship between study time and exam performance. Pearson's is approximately zero. What does this result primarily indicate?

49 For a bivariate normal population, a researcher tests with and obtains . Using , which conclusion is closest?

50 If the reliability of is .64 and the reliability of is .81, and the observed correlation is .36, what is the estimated disattenuated correlation?

51 A criterion correlates with predictors and at and , while . What is the squared multiple correlation?

52 A predictor correlates with a criterion at . After adding a second predictor, the multiple correlation is . What does the second predictor contribute?

53 A model with three predictors has . The zero-order correlations between the criterion and the predictors are all positive. Which conclusion is still possible?

54 Two predictors correlate at , and each correlates with at approximately . What is the primary statistical concern?

55 A regression model's rises from .36 to .49 when two predictors are added. Which statement is correct?

56 For six participants with no tied ranks, the squared rank differences sum to . What is Spearman's rank-order correlation?

57 A researcher ranks five observations on two variables. The rank pairs are . What is ?

58 When tied ranks occur, which procedure is generally most appropriate for computing Spearman's correlation?

59 Which pattern can produce a high Spearman correlation but a much smaller Pearson correlation?

60 If every rank on one variable is transformed from to , while the other variable remains unchanged, what happens to Spearman's correlation?