Statistics Questions - Please complete within 1 hour. 1.) Suppose there are two events, A and B. A and B are mutually exclusive. P(A)=.4, P(B)=.5. What is P(A??B?)? 2.) Suppose there are two elementary schools in a county. One school (A) loans all its students a laptop computer for use in classes. The other (B) does not. We would like to compare performance on a standardized test for the two groups of students. There are 28 students randomly chosen from school A and 34 from school b. The average test score for A is 78, and for B is 75. The sample standard deviation for A is 7 and for B is 10. While the population variances are unknown, we will assume they are equal. a. What is the 99% confidence interval for the difference between the two school?s scores. (For consistency, let the difference d=A-B.) b. Suppose we want to perform a two-tailed test where H0 is that ?d=0. What is (approximately) the p-value of the test? 3.) A car manufacturer claims that its vehicles average at least 25 miles per gallon, with a population standard deviation of ?=2. We take a sample of n=36 cars to test fuel efficiency, and with to performance a one-sided hypothesis test of the manufacturer?s claim at a level of ?=.05. a. What is the critical value for the sample mean? b. Suppose the answer to part a is 23.5 (it is not, but assume it is to do part b). If the true value of efficiency in the population is 22.75, what is the power of this hypothesis test?
Paper#13530 | Written in 18-Jul-2015Price : $25