1) The standard deviation of daily returns of a stock's price is used as a measure of the risk of that stock. Suppose that in a sample of 101 days, the standard deviation of a particular stock is 1.15%. a) In the past, the standard deviation of the daily returns of this stock has been 1.56%. Test the hypothesis at the 1% level of significance that the standard deviation has decreased from its previous level. 2) The US Tennis Association is considering switching the type of tennis ball used for it tournament events. For a brand of balls to be "acceptable" to the USTA, when dropped from a certain height, the balls must bounce an average of at least 4 feet. The USTA is reasonable happy with the current balls they use, but would be willing to switch to a new brand if they were confident that the new brand of balls were more consistent (had a lower variance) compared to the current balls they use. The standard deviation of the heights the current brand of balls bounced when dropped used is .48 feet. In a sample of 91 balls from the new brand being tested, the sample standard deviation is 38 feet. At the 5% level of significance, is there enough evidence that the new balls are more consistent (have a lower variance) than the current brand