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5.2 The Uniform Distribution

A flat density over an interval, probabilities read as rectangle areas, percentiles solved back from those areas, and conditional questions on a shortened interval.

Introductory Statistics 2e, 5.2 The Uniform Distribution

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17 exercises

5.2 Exercise 13

The distribution can be written as X ~ U(1.5, 4.5).

In this distribution, outcomes are equally likely. What does this mean?

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5.2 Exercise 15

The distribution can be written as X ~ U(1.5, 4.5).

What are the constraints for the values of x?

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5.2 Exercise 17

The distribution can be written as X ~ U(1.5, 4.5).

What is P(2 < x < 3)?

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5.2 Exercise 19

The distribution can be written as X ~ U(1.5, 4.5).

What is P(x = 1.5)?

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5.2 Exercise 21

The distribution can be written as X ~ U(1.5, 4.5).

Find the probability that a randomly selected home has more than 3,000 square feet given that you already know the house has more than 2,000 square feet.

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5.2 Exercise 23


Use the following information to answer the next eight exercises. A distribution is given as X ~ U(0, 12).

What is b? What does it represent?

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5.2 Exercise 25


Use the following information to answer the next eight exercises. A distribution is given as X ~ U(0, 12).

What is the theoretical mean?

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5.2 Exercise 29


Use the following information to answer the next eight exercises. A distribution is given as X ~ U(0, 12).

Find the 40th percentile.

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5.2 Exercise 31


Use the following information to answer the next eleven exercises. The age of cars in the staff parking lot of a suburban college is uniformly distributed from six months (0.5 years) to 9.5 years.

In words, define the random variable X.

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5.2 Exercise 33


Use the following information to answer the next eleven exercises. The age of cars in the staff parking lot of a suburban college is uniformly distributed from six months (0.5 years) to 9.5 years.

The interval of values for x is ______.

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5.2 Exercise 35


Use the following information to answer the next eleven exercises. The age of cars in the staff parking lot of a suburban college is uniformly distributed from six months (0.5 years) to 9.5 years.

Write the probability density function.

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5.2 Exercise 37


Use the following information to answer the next eleven exercises. The age of cars in the staff parking lot of a suburban college is uniformly distributed from six months (0.5 years) to 9.5 years.

Find the average age of the cars in the lot.

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5.2 Exercise 43

For each probability and percentile problem, draw the picture.

A random number generator picks a number from one to nine in a uniform manner.

  1. X ~ _________
  2. Graph the probability distribution.
  3. f(x) = _________
  4. μ = _________
  5. σ = _________
  6. P(3.5 < x < 7.25) = _________
  7. P(x > 5.67)
  8. P(x > 5|x > 3) = _________
  9. Find the 90th percentile.
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5.2 Exercise 45

For each probability and percentile problem, draw the picture.

A subway train arrives every eight minutes during rush hour. We are interested in the length of time a commuter must wait for a train to arrive. The time follows a uniform distribution.

  1. Define the random variable. X = _______
  2. X ~ _______
  3. Graph the probability distribution.
  4. f(x) = _______
  5. μ = _______
  6. σ = _______
  7. Find the probability that…
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5.2 Exercise 47

Use the following information to answer the next three exercises. The Sky Train from the terminal to the rental–car and long–term parking center is supposed to arrive every eight minutes. The waiting times for the train are known to follow a uniform distribution.

What is the average waiting time (in minutes)?

  1. zero
  2. two
  3. three
  4. four
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5.2 Exercise 49

Use the following information to answer the next three exercises. The Sky Train from the terminal to the rental–car and long–term parking center is supposed to arrive every eight minutes. The waiting times for the train are known to follow a uniform distribution.

The probability of waiting more than seven minutes given a person has waited more than four minutes is?

  1. 0.125
  2. 0.25
  3. 0.5
  4. 0.75
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5.2 Exercise 53

Use the following information to answer the next three exercises. The Sky Train from the terminal to the rental–car and long–term parking center is supposed to arrive every eight minutes. The waiting times for the train are known to follow a uniform distribution.

The number of miles driven by a truck driver falls between 300 and 700, and follows a uniform distribution.

  1. Find the probability that t…
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Adapted from Introductory Statistics 2e © 2023 Rice University. Licensed under CC BY 4.0. Source: Introductory Statistics 2e. Imported at revision 50ec917.