Chapter-6-worked-problems

# Chapter-6-worked-problems - Chapter 6 Answers to selected...

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1 Chapter 6 worked problems 2/1/2010 Chapter 6 Answers to selected problems 6.4 Grade Distribution x (grade as a number ex. 4 = A) P(x) (probability that a student would get this grade) xP(x) (multiply the x by the P(x) to find the μ) 1 0.1 0.1 2 0.3 0.6 3 0.4 1.2 4 0.2 0.8 ∑P(x) = 1 µ = ∑xP(x) = 2.7 The mean is 2.7 which means that a randomly selected student in the class got a grade of 2.7 which is either a C or C+ depending how the grading scale goes. 6.49 Grandparents x (no. of living grandparents) P(x) (probability of an adult in the study having this many) xP(x) (multiply the x by the P(x) to find the μ) 0 0.71 0 1 0.15 0.15 2 0.09 0.18 3 0.03 0.09 4 0.02 0.08 ∑P(x) = 1 µ = ∑xP(x) = 0.5 a. This is a discrete random variable because you can’t have a fractional grandparent. b. The two conditions are satisfied because a. 0 < P(x) < 1 Individual probabilities are between 0 and 1 b. ∑P(x) = 1 c. The mean of the probability distribution = 0.5. This means, on average, a randomly selected

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Chapter-6-worked-problems - Chapter 6 Answers to selected...

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