Assume that z scores are normally distributed with a mean of 0 and a standard deviation of 1. If P(a < z < 0) = 0.3907, find a. (A) qnorm(0.3907) = -0.2775 *** qnorm(0.1093) = -1.2303 (B) (C) qnorm(0.7814) = 0.7769301 (D) None of the above.

The answer is B and could you explain why?

Minnesota baby birth weights are skewed to the left. Which of the following best describes the shape of the sampling distribution of the average birth weight of a random sample of 233 Minnesota newborn babies? ***

(A) Symmetric (B) Skewed to the right (C) Skewed to the left (D) Bimodal

The answer is A could you explain why?

Let Y = the number of hours a student studies for the first 3011 midterm. From previous semesters we know that Y ∼ N(6, 1.5). What is the probability that for 100 randomly chosen students, their mean study time will be more than 6.3 hours?

(A) .025 (B) .050 (C) .500 (D) There is not enough information to answer this question

The answer is A, could you explain