Problem Solving

1. For a sample of n = 20 individuals, what correlation coefficient is necessary to be statistically significant at =.05?

1. Suppose the correlation between QPI and happiness level for college students is +.80. What percent of the variability in happiness level can be explained by the relationship with QPI?

1. The correlation coefficient is calculated for a sample of n = 25 individuals. What value of df should be used to determine whether or not the correlation is significant?

1. A set on n = 5 pairs of X and Y values has SSx = 10, SSy = 40 and SP = 10. Based on this information, what is the correlation coefficient?

1. A linear regression has b = 2 and a = 3. What is the predicted value of Y for X = 8?

1. A set of X and Y scores has SSx = 10, SSy = 20, and SP = 8. What is the slope for the regression equation?

1. A set of n = 25 pairs of scores (X and Y values) has a correlation coefficient of r = .60. How much of the variance of the Y scores is accounted for by the relationship with X?

1. The entrance fee for a theme park is 200.00 pesos. Tickets for each ride and attraction are 50.00 pesos a piece. What is the equation that describes the relationship between the total cost (Y) and the number of tickets purchased (X) in a single visit to the park?

1. If the correlation between X and Y is r = .30 and SSx = 100, how much of the variability of the Y scores is not accounted for by its relationship with X?