# Stat 160 Postquiz 5, Over Sections 4.4-5.3

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1. A carpenter measures (unifomly) within an eighth of an inch before cutting a piece of wood designed for a cabinet. However, the cut must be within a sixteenth of an inch to be useable. What is the probability that the piece cut by the carpenter is usable?

0.30
0.20
0.50
0.00

2. If you guess on each of the 12 questions on a quiz, what is the probability that you will get 8 or more correct answers? There are four choices in every question, and only one of them is correct. (Hint: This is a binomial problem)

0.9802
0.0198
0.0028
0.9972

3. Consider Problem (2). Determine the probability of exactly 5 correct answers.

.9802
.1032
.0544
.9456

4. Consider Problem (2). What is the variance of the number of correct answers?

5
0
2.25
3

5. The amount paid out by Ajax Insurance Company in a given year is normally distributed with mean 6 billion dollars and standard deviation .5 billion dollars. They consider it a bad year if they have to pay out more than 7.25 billion dollars. Determine the probability of a bad year. (Hint: Use one of the probability distributions in the Class Codes)

0.99379
0.00621
0.5000
0.025