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Chapter 5: Q8 (page 220)

In Exercises 6–10, use the following: Five American Airlines flights are randomly selected, and the table in the margin lists the probabilities for the number that arrive on time (based on data from the Department of Transportation). Assume that five flights are randomly selected.

Based on the table, the standard deviation is 0.9 flight. What is the variance? Include appropriate units.

x

P(x)

0

0+

1

0.006

2

0.051

3

0.205

4

0.409

5

0.328

Short Answer

Expert verified

The variance is 0.8flight2.

Step by step solution

01

Given information

The probability distribution for the five American airlines flights.

The standard deviation is 0.9 flight.

02

Calculate the variance

Let x represents the number of flights that arrive on time.

The variance is defined to be the square of the standard deviation.

The variance for random variable x is computed as,

σ2=σ2=0.92=0.81≈0.8

Thus, the variance is 0.8flight2.

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