Refer to Exercise 7.3 on page 295 .

a. Use your answers from Exercise 7.3(b) to determine the mean, μs. of the variable x¯ for each of the possible sample sizes.

b. For each of the possible sample sizes, determine the mean, μi, of the variable x~, using only your answer from Exercise 7.3(a).

Short Answer

Expert verified

a). The variable xhas a mean μx¯of 2.

b). The average for the population is 2.

Step by step solution

01

Part (a) Step 1: Given Information

Data on the population: 1,2,3

02

Part (a) Step 2: Explanation

For the variable x, we have population data, which is 1,2,3.

The mean μx¯of the variable role="math" localid="1650963041682" xfor each of the samples is calculated as follows:

The sample and sample means for a sample of size n=1are shown in the table below.

Sample x
11
22
33

The following is the mean μx¯for the variable x:

μx¯=1+2+33

=63

=2

As a result, the variable x has a mean x=2.

03

Part (a) Step 3: Explanation

The sample and sample means for a sample of size n=2are shown in the table below.

Sample x
1,2 1+22=1.5
2,3 1+32=2.0
3,1 2+32=2.5

The following is the mean μx¯for the variable x:

μx¯=1.5+2+2.53

=63

=2

04

Part (a) Step 4: Explanation

The sample and sample mean for a sample of size n=3are shown in the table below.

Sample x
1,2,3 1+2+33=2.0

The following is the mean μx¯for the variable x:

μx¯=2.01

=2

All the sample means are equal.

05

Part (b) Step 1: Given Information

Data on the population :1,2,3.

06

Part (b) Step 2: Explanation

The following is a definition of the population mean:

μ=xiN

=1+2+33

=2

We can see that μx¯=μ=2by combining the results of parts (a) and (b).

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.

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

7.50 Undergraduate Binge Drinking. Alcohol consumption on college and university campuses has gained attention because undergraduate students drink significantly more than young adults who are not students. Researchers I. Balodis et al. studied binge drinking in undergraduates in the article "Binge Drinking in Undergraduates: Relationships with Gender, Drinking Behaviors, Impulsivity, and the Perceived Effects of Alcohol" (Behavioural Pharmacology, Vol. 20, No. 5. pp. 518-526). The researchers found that students who are binge drinkers drink many times a month with the span of each outing having a mean of 4.9hours and a standard deviation of 1.1 hours.
a. For samples of size 40, find the mean and standard deviation of all possible sample mean spans of binge drinking episodes. Interpret your results in words.
b. Repeat part (a) with n=120.

America's Riches. Each year, Forbes magazine publishes a list of the richest people in the United States. As of September l6, 2013, the six richest Americans and their wealth (to the neatest billion dollars) are as shown in the following table. Consider these six people a population of interest.

(a) For sample size of 6construct a table similar to table 7.2 on page293 what is the relationship between the only possible sample here and the population?

(b) For a random sample of size 6determine the probability that themean wealth of the two people obtained will be within 3(i.e,3 billion) of the population mean. interpret your result in terms of percentages.

Loan Amounts. B. Ciochetti et al. studied mortgage loans in the article "A Proportional Hazards Model of Commercial Mortgage Default with Originator Bias" (Joumal of Real Exfate and Economics, Vol, 27. No. 1. pp. 5-23). According to the article, the loan amounts of loans originated by a large insurance-company lender have a mean of \(6.74 million with a standard deviation of \)15.37 million. The variable "loan amount" is known to have a right-skewed distribution.

a. Using units of millions of dollars, determine the sampling distribution of the sample mean for samples of size 200 . Interpret your result.

b. Repeat part (a) for samples of size 600

c. Why can you still answer parts (a) and (b) when the distribution of loan amounts is not normal, but rather right skewed?

d. What is the probability that the sampling error made in estimating the population mean loan amount by the mean loan amount of a simple random sample of 200 loans will be at most $1 million?

e. Repeat part (d) for samples of size 600

America's Riches. Each year, Forbes magazine publishes a list of the richest people in the United States. As of September l6, 2013, the six richest Americans and their wealth (to the neatest billion dollars) are as shown in the following table. Consider these six people a population of interest.

(a) For sample size of 5construct a table similar to table 7.2 on page293.(There are 6 possible sample) of size 5

(b) For a random sample of size 5determine the probability that themean wealth of the two people obtained will be within 3(i.e,3billion) of the population mean. interpret your result in terms of percentages.

Ethanol Railroad Tariffs. An ethanol railroad tariff is a fee charged for shipments of ethanol on public railroads. The Agricultural Marketing Service publishes tariff rates for railroad-car shipments of ethanol in the Biofuel Transportation Database. Assuming that the standard deviation of such tariff rates is \(1,150, determine the probability that the mean tariff rate of 500randomly selected railroad car shipments of ethanol will be within \)100of the mean tariff rate of all railroad-car shipments of ethanol. Interpret your answer in terms of sampling error.

See all solutions

Recommended explanations on Math Textbooks

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