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MAT 155 Lab 2

Sections 3.1-3.5 Fundamentals of Probability

Date ______Student’s Name______Row___ Seat___ Score____

Lab2FundProb

1. Find each of the following probabilities:

a. If P(A) = 0.332, find P().

b. Based on data from the National Health Examination, the probability of a randomly selected adult male being taller that 6 ft is 0.14. Find the probability of randomly selecting an adult male and getting someone with height of 6 ft or less.

2. In a study of 82 young (under the age of 32) drivers, 39 were men who were ticketed, 11 were men who were not ticketed, 8 were women who were ticketed, and 24 were women who were not ticketed (based on data from the Department of Transportation). If one of these subjects is randomly selected, find the probability of getting a man or someone who was not ticketed.

3. Determine whether the following events are mutually exclusive (or disjoint):

a. If P(A) = 3/11, P(B) = 4/11, and P(A or B) = 7/11, what do you know about events A and B?

b. If P(A) = 3/18, P(B) = 11/18, and P(A or B) = 13/18, what do you know about events A and B?

4. A pool of potential jurors consists of 15 men and 12 women. If two different people are randomly selected from this pool, find the probability that they are both women.

5. A quick quiz consists of four multiple-choice questions, each with five possible answers, only one of which is correct. If you make random guesses for each answer, what is the probability that all four of your answers are wrong?

6. A classic excuse for a missed test is offered by four students who claim that their car had a flat tire. On the makeup test, the instructor asks the students to identify the particular tire that went flat. If they really didn’t have a flat tire and randomly select one that supposedly went flat, what if the probability that they will all select the same tire?

7. Match the following approaches to probability by placing the correct letter in the blank. Each letter should be used no more than once.

____ (a) Assume that a given procedure has n different simple events and that each of those simple events has an equal chance of occurring.

____ (b) Conduct (or observe) a procedure a large number of times, and count the number of times that event actually occurs.

____ (c) The probability is found by simply guessing or estimating its value based on knowledge of the relevant circumstances.

A. Subjective probability B. Relative frequency probability C. Classical probability

8. Draw a tree diagram to illustrate the possible births of three children in a family and find the probability of the birth of exactly two (2) boys.

9. Assume the ages of past, present, and future presidents have a bell-shaped distribution with a mean of 54.8 yeas and a standard deviation of 6.2 years.

(a) What does the empirical rule say about the percentage of ages between 48.6 years and 61.0 years (or within 1 standard deviation of the mean)?

(b) What does the empirical rule say about the percentage of ages between 42.4 years and 67.2 years?

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