Question

10. 6.66/10 points | Previous Answers WaneFMAC7 9.4.043. My Notes According to a study, the probability that a randomly selected teenager shopped at a mall at least once during a week was 0.63. Let X be the number of students in a randomly selected group of 50 that will shop at a mall during the next week. (a) Compute the expected value and standard deviation of X. (Round your answer to two decimal places.) Hint [See Example 5,] expected value 31.5 standard deviation 3.41 (b) Fill in the missing quantity. (Round your answer to the nearest whole number.) There is an approximately 2.5% chance that 25 or more teenagers in the group will shop at the mall during the next week Submit Answer Save Progress Practice Another Version

Answer 1

(b)

Let X is a ranodm variable shows the number of teenagers in the group will shop at the mall next week. here we need x such that

Let X is a ranodm variable shows the number of teenagers in the group will shop at the mall next week. here we need x such that p(x greaterthanequalto x) = 0.025 here we need z-score that has 0.025 area to its right. The z-score 1.96 has 0.025 area to its right. The requried X is z = x - E(X)/SD(X) 1.96 = X - 31.5/3.41 X = 38.1836 almostequalto 39

here we need z-score that has 0.025 area to its right. The z-score 1.96 has 0.025 area to its right.

The requried X is