Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 2: Q 78. (page 142)

Are body weights Normal? The heights of people of the same gender and similar ages follow Normal distributions reasonably closely. How about body weights? The weights of women aged 20 to 29 have mean 141.7 pounds and median 133.2pounds. The first and third quartiles are 118.3 pounds and 157.3pounds. Is it reasonable to believe that the distribution of body weights for women aged 20to 29 is approximately Normal? Explain

your answer.

Short Answer

Expert verified

No.

Step by step solution

01

Given information

Mean =141.7

Median =133.2

First quartile=118.3

Third quartile =157.3

02

Concept

The distance between the minimum and maximum values from the mean must be the same for the distribution to be normal.

03

Explanation

The median is higher than the mean in this case. As a result, it's possible to deduce that the distribution is skewed to the right. The fact that the distribution is skewed to the right indicates that the data was not collected from a regularly distributed population. As a result, it is impossible to infer that women's body weight distribution is typical.

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

I think I can! Refer to Exercise 55. The locomotive’s manufacturer is considering two changes that could reduce the percent of times that the train arrives late. One option is to increase the mean adhesion of the locomotive. The other possibility is to decrease the variability in adhesion from trip to trip, that is, to reduce the standard deviation.

(a) If the standard deviation remains at σ=0.04, to what value must the manufacturer change the mean adhesion of the locomotive to reduce its proportion of late arrivals to less than 2%of days? Show your work.

(b) If the mean adhesion stays atμ=0.37, how much must the standard deviation be decreased to ensure that the train will arrive late less than 2%of the time? Show your worK

(c) Which of the two options (a) and (b) do you think is preferable?. justify your answer. (Be sure to consider the effect of these changes on the percent of days that the train arrives early to the switch point)

Measure up Clarence measures the diameter of each tennis ball in a bag with a standard ruler. Unfortunately, he uses the ruler incorrectly so that each of his measurements is 0.2inchtoo large. Clarence’s data had a mean of 3.2inchesand a standard deviation of 0.1inch (Recall that 1in.=2.54cm)

a. Find the mean of the corrected measurements in centimeters.

b. Calculate the standard deviation of the corrected measurements in centimeters.

Potato chips Refer to Exercise 47 About what percent of 9-ounce bags of

this brand of potato chips weigh less than the advertised 9 ounces? Is this likely to pose a problem for the company that produces these chips?

Step right up! Refer to Exercise 22 Suppose that the distances from the tops of the students’ heads to the ground are converted from inches to feet (note that 12in.=1ft).

a. What shape would the resulting distribution have? Explain your answer.

b. Find the mean of the distribution of distance in feet.

c. Find the standard deviation of the distribution of distance in feet.

Comparing bone density Refer to Exercise 17 Judy’s friend Mary also had the bone density in her hip measured using DEXA. Mary is 35 years old. Her bone density is also reported as 948g/cm2 but her standardized score is z=0.50 The mean bone density in the hip for the reference population of 35-year-old women is 944grams/cm2

a. Whose bones are healthier for her age: Judy’s or Mary’s? Justify your answer.

b. Calculate the standard deviation of the bone density in Mary’s reference population. How does this compare with your answer to Exercise 17(b)? Are you surprised?
See all solutions

Recommended explanations on Math Textbooks

Logic and Functions

Read Explanation

Pure Maths

Read Explanation

Discrete Mathematics

Read Explanation

Theoretical and Mathematical Physics

Read Explanation

Mechanics Maths

Read Explanation

Statistics

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