In a memory retention experiment, subjects were asked to memorize a list of disconnected items, and then were asked to recall them at various times up to a week later. The proportion (Prop) of items recalled at a certain time (in minutes) was recorded for 13 subjects. Time required a natural log transformation. The least-squares estimate of the regression line was:
μˆ (Prop | ln(Time) = 0.846 - 0.079Ln(Time)
In addition, the sample correlation coefficient between Prop and ln(Time) was -0.995.
a) What percentage of variability in Prop is explained by ln(Time)?
b) What is the value of the F-statistic in the ANOVA table?
c) What is the value of the test statistic for testing H0: β1 = 0 versus HA: β1 < 0 ?
d) What is the standard error of the estimated slope for the regression line?