1. The following observations were made on fracture toughness of a base plate of 18% nickel maraging steel (in ksi in, given in increasing order)]: 65.1 71.9 72.7 73.1 73.1 73.5 75.5 75.7 75.8 76.1 76.2 76.2 77.0 77.9 78.2 79.6 79.7 79.9 80.1 82.2 83.5 93.5 Calculate a 99% CI for the standard deviation of the fracture toughness distribution. (Round your answers to one decimal place.)
2. It is thought that the front cover and the nature of the first question on mail surveys influence the response rate. An article tested this theory by experimenting with different cover designs. One cover was plain; the other used a picture of a skydiver. The researchers speculated that the return rate would be lower for the plain cover. (data shown in pic below) Does this data support the researchers' hypothesis? Test the relevant hypotheses using = 0.10 by first calculating a P-value. H0:p1p2=0 Ha:p1p2<0 Compute the test statistic value and find the P-value. (Round your test statistic to two decimal places and your P-value to four decimal places.)