Referring to Exercise 7, suppose that the standard deviationof the random deviation e is 350 psi.a. What is the probability that the observed value of28-day strength will exceed 5000 psi when the valueof accelerated strength is 2000?b. Repeat part (a) with 2500 in place of 2000.c. Consider making two independent observations on28-day strength, the first for an accelerated strengthof 2000 and the second for x 5 2500. What is theprobability that the second observation will exceedthe first by more than 1000 psi?d. Let Y1 and Y2 denote observations on 28-day strengthwhen x 5 x1 and x 5 x2, respectively. By how muchwould x2 have to exceed x1 in order that P(Y2 . Y1) 5.95?

MSIT UNIT 9 – Sampling Distributions & Confidence Intervals for Proportions p –true proportion of success in a pop. is constant; parameter pp –the sample proportion of Parameter (fixed)of a population is the proportion of success in a succe(relative frequency) population (we can observe a sample, but probably won’t find the true value of the parameter) n –sample size P np –expected # successe