A random sample of 100 daily stock returns was taken. Theaverage return in the sample appeared to be 4.81%. The populationstandard deviation is not known, but the sample standard deviationis known to be 0.9%.
a.  Calculate a 95% confidence interval for theaverage stock return
b. How big the sample size be for the margin of error of 0.1% atthe confidence level 95%?
c. A fund manager claims that the average stock return is higherthan 4.81%. Test the fund manager’s claim with the 5% level ofsignificance.
