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Statistics for Decision- Making in Business - Maricopa Community ...

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Then the sum of the two triangular areas is:<br />

In this next section, we will focus our attention on the most commonly used cont<strong>in</strong>uous random<br />

variable: the normally distributed random variable.<br />

Homework Problems –5.1<br />

The first two questions below <strong>in</strong>volve discrete random variables. The aim of these questions is to<br />

get you th<strong>in</strong>k<strong>in</strong>g <strong>in</strong> terms of the probabilities of ranges of values.<br />

1. A pizza shop sells pizzas <strong>in</strong> four different sizes. The 1000 most recent orders <strong>for</strong> a s<strong>in</strong>gle<br />

pizza gave the follow<strong>in</strong>g proportions <strong>for</strong> the various sizes:<br />

With denot<strong>in</strong>g the size of a pizza <strong>in</strong> a s<strong>in</strong>gle-pizza order, the given table is an<br />

approximation to the population distribution of .<br />

a. Construct a probability (relative frequency) histogram to represent the<br />

approximate distribution of this variable.<br />

b. Approximate ( ).<br />

c. Approximate ( ).<br />

d. F<strong>in</strong>d the expected value of .What does this value mean<br />

e. What is the approximate probability that is with<strong>in</strong> 2 <strong>in</strong>. of this expected (mean)<br />

value<br />

2. Airl<strong>in</strong>es sometimes overbook flights. Suppose that <strong>for</strong> a plane with 100 seats, an airl<strong>in</strong>e<br />

takes 110 reservations. Def<strong>in</strong>e the variable as the number of people who actually show<br />

up <strong>for</strong> a sold-out flight. From past experience, the population distribution of is given <strong>in</strong><br />

the follow<strong>in</strong>g table:<br />

<strong>Statistics</strong> <strong>for</strong> <strong>Decision</strong>-<strong>Mak<strong>in</strong>g</strong> <strong>in</strong> Bus<strong>in</strong>ess © Milos Podmanik Page 168

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