Suppose that, for a sample of pairs of observations from two variables, the linear correlation coefficient, r , is negative. Does this result necessarily imply that the variables are negatively linearly correlated? Explain.
The following advanced exercise use a generalized ratio test to determine convergence of some series that arise in particular applications, including the ratio and root test, are not powerful enough to determine their convergence. The test states that if $$
The average credit card debt for a recent year was $9205. Five years earlier the average credit card
debt was $6618. Assume sample sizes of 35 were used and the population standard deviations of
both samples were $1928. Find the 95% confidence interval of the difference in means.