Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 6: Q. 6.127 (page 285)

A sample of final exam scores in a large introductory statistics course is as follows.

Part (a): Use Table III in Appendix A to construct a normal probability plot of the given data.

Part (b): Use part (a) to identify any outliers.

Part (c): Use part (a) to access the normality of the variable under consideration.

Short Answer

Expert verified

Part (a): The required normal probability plot is given below,

Part (b): On identifying the outliers, we get 34and 39.

Part (c): Final-exam scores in this introductory statistics class do not appear to be normally distributed.

Step by step solution

01

Part (a) Step 1. Given information.

Consider the given question,

02

Part (a) Step 2. Construct a normal probability plot.

The variable is final exam score. To construct a normal probability plot, we first arrange the data in increasing order and obtain the normal scores from normal scores table.

The ordered data are shown in the first column of the below table; the normal scores form n=20column of normal scores table, are shown in the second column of the below table.

03

Part (a) Step 3. Plot the points.

Plot the points using horizontal axis for the final exam scores and the vertical axis for the normal scores,

04

Part (b) Step 1. Identify any outliers.

Consider the normal probability plot from part (a),

We can observe the final exam scores, 34,39are outliers.

These two observations fall outside the overall pattern of the data.

05

Part (c) Step 1. Access the normality of the variable under consideration.

Consider the normal probability plot from part (a),

The above normal probability plot is not roughly linear. So, we can assume that the final exam score is not approximately normally disturbed.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Use Table to obtain the areas under the standard normal curve. Sketch a standard normal curve and shade the area of interest in each problem.

Find the area under the standard normal curve that lies

a. either to the left of -1or to the right of 2.

b. either to the left of -2.51or to the right of -1.

Property 4of Key Fact 6.5states that most of the area under the standard normal curve lies between -3and 3. Use Table II to determine precisely the percentage of the area under the standard normal curve that lies between -3 and 3.

Philosophical and health issues are prompting an increasing number of Taiwanese to switch to a vegetarian lifestyle. In the paper "LDL of Taiwanese Vegetarians Are Less Oxidizable than Those of Omnivores" (Journal of Nutrition, Vol. 130, Pp. 1591-1596), S. Lu et al. compared the daily intake of nutrients by vegetarians and omnivores living in Taiwan. Among the nutrients considered was protein. Too little protein stunts growth and interferes with all bodily functions; too much protein puts a strain on the kidneys, can cause diarrhea and dehydration, and can leach calcium from bones and teeth. The daily protein intakes, in grams, for 51 female vegetarians and 53 female omnivores are provided on the Weiss Stats site. Use the technology of your choice to do the following for each of the two sets of sample data.

a. Obtain a histogram of the data and use it to assess the (approximate) normality of the variable under consideration.

b. Obtain a normal probability plot of the data and use it to assess the (approximate) normality of the variable under consideration.

c. Compare your results in parts (a) and (b).

A variable is normally distributed with a mean 10 and standard deviation3. Find the percentage of all possible values of the variable that

a. lie between 6and 7.

b. are at least 10 .

c. are at most 17.5 .

11. Answer true or false to each statement. Explain your answers.

a. Two normal distributions that have the same mean are centered at the same place, regardless of the relationship between their standard deviations.

b. Two normal distributions that have the same standard deviation have the same spread, regardless of the relationship between their means.
See all solutions

Recommended explanations on Math Textbooks

Pure Maths

Read Explanation

Probability and Statistics

Read Explanation

Discrete Mathematics

Read Explanation

Logic and Functions

Read Explanation

Theoretical and Mathematical Physics

Read Explanation

Calculus

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free