Question

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 student, it was found that x has an approximately normal distribution with mean u=6.8 hours and standard deviation =2.1 hours.

Convert each of the following x intervals to standardized z intervals

1. x < 7.5
2. 5 < x < 8

Using the above information, convert each of the following z intervals to raw score x intervals.

1. z > -2
2. 0 < z < 2

Weights of a certain model of fully loaded gravel trucks follow a normal distribution with mean = 6.4 tons and standard deviation = 0.3 ton. What is the probability that a fully loaded truck of this model is

1. less than 6 tons?
2. between 6 and 7 tons?

Answer 1