Skip to content Skip to navigation

Connexions

You are here: Home » Content » Elementary Statistics: Exam 3: Lessons 5, 6 & 7

Navigation

Recently Viewed

This feature requires Javascript to be enabled.

Elementary Statistics: Exam 3: Lessons 5, 6 & 7

Module by: Susan Dean, Barbara Illowsky, Ph.D.. E-mail the authors

User rating (How does the rating system work?)
Ratings

Ratings allow you to judge the quality of modules. If other users have ranked the module then its average rating is displayed below. Ratings are calculated on a scale from one star (Poor) to five stars (Excellent).

How to rate a module

Hover over the star that corresponds to the rating you wish to assign. Click on the star to add your rating. Your rating should be based on the quality of the content. You must have an account and be logged in to rate content.

:
(0 ratings)

Summary: Practice final exam for use with Collaborative Statistics (col10522) by Barbara Illowsky and Susan Dean.

Questions 1 – 3 refer to the following:

Assume the amount of money seventh–grade students spend on food each day at school is exponentially distributed with an average of $2.50.

Exercise 1

Which graph best describes the distribution?

  • A. An exponentially decreasing function in the first quadrant. The function crosses the y-axis at 2.5 and nears the x-axis at 1/2.5
  • B. An exponentially decreasing function in the first quadrant. The function crosses the y-axis at 1/2.5 and nears the x-axis at 2.5
  • C. An exponentially decreasing function in the first quadrant. The function crosses the y-axis at 2.5 and nears the x-axis at 2.5
  • D. An exponentially decreasing function in the first quadrant. The function crosses the y-axis at 1/2.5 and nears the x-axis at 1/2.5

Solution

B

Exercise 2

Find the probability that a randomly selected seventh–grade student spends less than $4 a day on food.

  • A. 0.7981
  • B. 0.2019
  • C. 0.9999
  • D. 0.0001

Solution

A

Exercise 3

85% of the seventh–grade students spend more than what amount per day?

  • A. $2.12
  • B. $0.75
  • C. $4.74
  • D. $0.41

Solution

D

Questions 4 – 5 refer to the following:

The amount of time that intermediate algebra students at Leland High School spend doing their homework per day is normally distributed with a mean 1.5 hours and standard deviation 0.75 hours.

Exercise 4

If one student is randomly chosen, what is the probability that the student does intermediate algebra homework at least 2 hours per day?

  • A. 0.7475
  • B. 0.4259
  • C. 0.2525
  • D. 0.6784

Solution

C

Exercise 5

60% of these students spend at most how many hours doing their homework?

  • A. 1.69 hours
  • B. 1.31 hours
  • C. 1.5 hours
  • D. 0.2533 hours

Solution

A

Questions 6 – 7 refer to the following:

Llamas are excellent pack animals. It is known that the weight of supplies carried by llamas follows a normal distribution with a mean of 62.5 pounds and a standard deviation of 6 pounds.

Exercise 6

Find the probability that the weight of supplies carried by one randomly chosen llama is between 60 and 70 pounds.

  • A. 0.4441
  • B. 0.5559
  • C. 0.8944
  • D. 1

Solution

B

Exercise 7

The middle 50% of weights of supplies carried by a randomly chosen llama is between _____ and _____.

  • A. 0 and 62.5 pounds
  • B. 58.45 and 66.55 pounds
  • C. 56.5 and 68.5 pounds
  • D. There is not enough information given.

Solution

B

Exercise 8

Which of the following are true for the normal distribution?

  • I. More values fall close to the mean than fall far away from the mean.
  • II. The mean and standard deviation cannot be the same.
  • III. A change in µ causes the graph to shift to the left or right and changes the shape of the graph.
  • IV. A change in s causes a change in the shape of the normal curve.
  • A. I, IV
  • B. I, II, III, IV
  • C. I, II, III
  • D. III, IV

Solution

A

Questions 9 – 13 refer to the following:

The length of time junior high school students sleep per night follows an approximate uniform distribution from seven to eleven hours. Suppose we randomly select a junior high student.

Exercise 9

Find the probability that the randomly selected student sleeps less than 8 1/2 hours per night.

  • A. .2143
  • B. 0.7727
  • C. 0.4705
  • D. 0.375

Solution

D

Exercise 10

Find the probability that the randomly selected student sleeps eight to twelve hours per night.

  • A. 0
  • B. 1
  • C. 0.75
  • D. 0.25

Solution

C

Exercise 11

On average, how long does a junior high school student sleep per night?

  • A. .2143
  • B. 0.7727
  • C. 0.4705
  • D. 0.375

Solution

B

Exercise 12

On average, how long does a junior high school student sleep per night?

  • A. 9.6 hours
  • B. 6.5 hours
  • C. 7.8 hours
  • D. 8.4 hours

Solution

D

Exercise 13

We are interested in the probability that a randomly selected student sleeps less than eight hours, knowing that he/she sleeps less than ten. Which graph best depicts this situation?

  • A. A rectangular block reaching on the x-axis from 7 to 12, and on the y-axis from 0 to 1/5. The section from 7 to 8 on the x-axis is shaded in.
  • B. A rectangular block reaching on the x-axis from 7 to 12, and on the y-axis from 0 to 1/5. The section from 8 to 11 on the x-axis is shaded in.
  • C. A rectangular block reaching on the x-axis from 7 to 10, and on the y-axis from 0 to 1/3. The section from 7 to 8 on the x-axis is shaded in.
  • D. A rectangular block reaching on the x-axis from 7 to 10, and on the y-axis from 0 to 1/3. The section from 9 to 11 on the x-axis is shaded in.

Solution

C

Content actions

Give Feedback:

E-mail the module authors | Rate module ( How does the rating system work?)

Rating system

Ratings

Ratings allow you to judge the quality of modules. If other users have ranked the module then its average rating is displayed below. Ratings are calculated on a scale from one star (Poor) to five stars (Excellent).

How to rate a module

Hover over the star that corresponds to the rating you wish to assign. Click on the star to add your rating. Your rating should be based on the quality of the content. You must have an account and be logged in to rate content.

(0 ratings)

Download:

Module PDF

Add module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections directly in Connexions. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need a Connexions account to use 'My Favorites'.

| A lens (?)

Definition of a lens

Lenses

A lens is a custom view of Connexions content. You can think of it as a fancy kind of list that will let you see Connexions through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to Connexions materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual Connexions member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks