5. The data set memoryAl.rds comes from a longitudinal study on aging. Recorded variables are: execwl: a measure of cogn

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5 The Data Set Memoryal Rds Comes From A Longitudinal Study On Aging Recorded Variables Are Execwl A Measure Of Cogn 1 (58.04 KiB) Viewed 60 times

5. The data set memoryAl.rds comes from a longitudinal study on aging. Recorded variables are: execwl: a measure of cognitive function at the start of the study execw2: a measure of cognitive function 2 years later sex: whether participant is male or female. To read in the dataset use readRDS function: qubdata <- readRDS ("memory$1.rds") (a) Plot execw2 versus execwl. Does the relationship between the two variables look linear? item Compute the correlation for execwl and execw2. What is the p-value associ- ated with the correlation between execwl and execw2? State the hypotheses and conclusion. (b) Fit the simple linear regression model for execw2 versus execwl. State the equation of the estimated regression line. (c) Test the hypothesis that Bo = 0 versus the alternative that Bo +0. State the conclusions in the context of the data. Explain whether or not this is a worthwhile hypothesis to test in this case. (d) Calculate and interpret a 95% confidence interval for Bo. (e) Test the hypothesis that B1 = 0 versus the alternative that B1 +0. State your conclusions in the context of the data. Explain whether or not this is a worthwhile hypothesis to test in this case. (1) Calculate and interpret a 95% confidence interval for 31. (g) What is being tested by the F-test in the ANOVA table? State clearly the hypotheses, results and conclusions. (h) State the assumptions in the simple linear regression model fitted above. Determine whether or not the assumptions are satisfied.