Question 1 A certain manufacturer of chocolate bars claims that the weight of th

Question

Question 1

A certain manufacturer of chocolate bars claims that the weight of the chocolate bars is normally distributed, with a mean m = 8 ounces and a standard deviation of s = 0.1 ounces. If a random sample of n = 5 chocolate bars is selected, approximately what is the probability that the sample mean weight is less than 7.9 ounces? Use what you know about sampling distributions and the 68-95-99.7 Rule to choose the best answer among those given below, and explain just WHY you feel it is the best answer.

a. .01 (or 1%)

b. .16 (or 16%)

c. .33 (or 33%)

d. .99 (or 99%)

Question 2

The amount of money college students spend each semester on textbooks is normally distributed with a mean of $195 and a standard deviation of $20. Suppose you take a random sample of 100 college students from this population. There would be a 68% chance that the sample mean amount spent on textbooks would be between what two values? Please explain just how you arrived at your answer.

Explanation / Answer

(1) x-bar = 7.9, = 8, s = 0.1, n = 5

z = (x-bar - )/(s/n) = (7.9 - 8)/(0.1/5) = -2.2361

P(x-bar < 7.9) = P(z < -2.2361) = 0.0127 (1%)

Option (a).

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