Problem 6-7 The College Board reported the following mean scores for the three parts of the SAT: Critical Reading 502 Mathematics 515 Writing 494 Assume that the population standard deviation on each part of the test is = 100. If required, round your answers to two decimal places. (a) For a random sample of 30 test takers, what is the standard deviation of x for scores on the Critical Reading part of the test? (b) For a random sample of 60 test takers, what is the standard deviation of x for scores on the Mathematics part of the test? (c) For a random sample of 90 test takers, what is the standard deviation of x for scores on the Writing part of the test?