Question

1. (6 pts) Let x be a random variable that represents the length of time it takes a student to write a term paper for Dr. Adam’s sociology class. After interviewing many students, it was found that x has an approximate normal distribution with mean = 6.8 hours and standard deviation = 2.1 hours.

1. Convert the x interval x 4 to a standard z interval.

2. Convert the z-score interval 0 ≤ ? ≤ 2 to a raw score x interval.

Answer 1

1. There is no sign given between x and 4 so i will solve for all the 3 cases

a) x = 4

In z -interval it will be written as

b) x < 4 in z-interval is .

c) x > 4 in z-interval is .

2. The z score interval is

for z = 0, x is = 6.8 + 0*2.1 = 6.8

for z = 2, x is = 6.8 + 2*2.1 = 11

The x-interval is

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