Population data: 1,2,3,4,5,6

Part (a): Find the mean, μ, of the variable.

Part (b): For each of the possible sample sizes, construct a table similar to Table 7.2on the page 293and draw a dotplot for the sampling for the sampling distribution of the sample mean similar to Fig 7.1on page 293.

Part (c): Construct a graph similar to Fig 7.3and interpret your results.

Part (d): For each of the possible sample sizes, find the probability that the sample mean will equal the population mean.

Part (e): For each of the possible sample sizes, find the probability that the sampling error made in estimating the population mean by the sample mean will be 0.5or less, that is, that the absolute value of the difference between the sample mean and the population mean is at most 0.5.

Short Answer

Expert verified

Part (a): The mean μis localid="1652596850399" 3.5.

Part (b): When localid="1652596852524" n=1,

When localid="1652596854771" n=2,

When localid="1652596858104" n=3,

When localid="1652596861502" n=4,

When localid="1652596867295" n=5,

When localid="1652596883962" n=6,

Part (c): The dot plot is given below,

Part (d): The probability that the sample mean will equal the population mean are 0,15,0,15,0,1.

Part (e): The probability that the sampling error made in estimating the population are13,715,35,1115,1,1.

Step by step solution

01

Part (a) Step 1. Given information

Consider the given question,

The population data is1,2,3,4,5,6.

02

Part (a) Step 2. Find the mean of the variable.

The mean μis given below,

μ=xiN=1+2+3+4+5+66=216=3.5

03

Part (b) Step 1. Construct a table for n=1,2,3.

For each of the possible sample sizes, we construct a table.

If the sample size taken n=1,


If the sample size taken n=2,

If the sample size taken n=3,

04

Part (b) Step 2. Construct a table for n=4,5,6.

If the sample size taken n=4,

If the sample size taken n=5,

If the sample size taken n=6

05

Part (c) Step 1. Construct the dot plot.

We will construct the dot plot for the sampling distribution of the sample mean.

To construct dot plot for the sampling distribution of the sample mean,

06

Part (d) Step 1. Find the probability that the sample mean will equal the population mean.

We can observe that from the dot plot there is no dot corresponding to μ=3.5 when n is 1.

Hence, the probability that sample mean will be equal to population mean=06=0.

Similarly, the probability that sample mean will be equal to population mean when n is 2is 315=15(As there are 3dots corresponding μ=3.5)

The probability that sample mean will be equal to population mean when n is 3is 020=0(As there are 3dots corresponding μ=3.5)

We can observe that from the dot plot there is one dot corresponding to μ=5 when n is 4.

The probability that sample mean will be equal to population mean when n is 4is 315=15(As there are 3dots corresponding μ=3.5)

The probability that sample mean will be equal to population mean when n is 5is 06=0.

The probability that sample mean will be equal to population mean for n=6is 1.

07

Part (e) Step 1. Find the probability that sampling error made in estimating the population mean.

Number of dots within 0.5or less of role="math" localid="1652596657200" μ=3.5is 2out of 6 when n is 1.

Hence, the probability that xwill be within 0.5or less of μis 26=13.

Number of dots within 0.5or less of role="math" localid="1652596659615" μ=3.5is 7out of 15 when n is 2.

Hence, the probability that xwill be within 0.5or less of μis 715.

Number of dots within 0.5or less of role="math" localid="1652596662174" μ=3.5is 12out of 20 for n is 3.

Hence, the probability that xwill be within 0.5or less of μis 1220=35.

Number of dots within 0.5or less of role="math" localid="1652596648815" μ=3.5is 11out of 15 when nis 4.

Hence, the probability that xwill be within 0.5or less of μis 1115.

Number of dots within data-custom-editor="chemistry" 0.5or less of role="math" localid="1652596728978" μ=3.5is 6out of 6 when n is data-custom-editor="chemistry" 5.

Hence, the probability that xwill be within 0.5or less of μis 66=1.

Number of dots within 0.5or less of μ=3.5is 1out of 1 when n is 6.

Hence, the probability that xwill be within 0.5or less ofμis11=1.

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Most popular questions from this chapter

Repeat parts (b)-(e) of Exercise 7.11 for samples of size4.

Each years, Forbers magazine publishes a list of the richest people in the United States. As of September 16, 2013,the six richest Americans and their wealth (to the nearest billion dollars) are as shown in the following table. Consider these six people a population of interest.

Part (a): Calculate the mean wealth, μ, of the six people.

Part (b): For samples of size 2, construct a table similar to Table 7.2 on page 293. (There are 15 possible samples of size 2.)

Part (c): Draw a dotplot for the sampling distribution of the sample mean for samples of size 2.

Part (d): For a random sample of size2, what is the chance that the sample mean will equal the population mean?

Part (e): For a random sample of size 2, determine the probability that the mean wealth of the two people obtained will be within 3 of the population mean. Interpret your result in terms of percentages.

Provide two synonyms for the distribution of all possible sample means for samples of a given size.

In Example 7.5, we used the definition of the standard deviation of a variable to obtain the standard deviation of the heights of the five starting players on a men's basketball team and also the standard deviation of x for samples of sizes 1,2,3,4,5.The results are summarized in Table 7.6on page 298. Because the sampling is without replacement from a finite population, Equation (7.1) can also be used to obtain σx.

Part (a): Apply Equation (7.1) to compute σx for sample sizes of 1,2,3,4,5. Compare your answers with those in Table 7.6.

Part (b): Use the simpler formula, Equation (7.2) to compute σx for samples of sizes 1,2,3,4,5.Compare your answers with those in Table 7.6. Why does Equation (7.2)generally yield such poor approximations to the true values?

Part (c): What percentages of the population size are samples of sizes 1,2,3,4,5.

7.67 Brain Weights. In 1905, R. Pearl published the article "Biometrical Studies on Man. 1. Variation and Correlation in Brain Weight" (Biometrika, Vol. 4, pp. 13-104). According to the study, brain weights of S wedish men are normally distributed with a mean of 1.40kg and a standard deviation of 0.11kg

a. Determine the sampling distribution of the sample mean for samples of size 3 Interpret your answer in terms of the distribution of all possible sample mean brain weights for samples of three Swedish men.

b. Repeat part (a) for samples of size 12

c. Construct graphs similar to those shown in Fig. 7.4on page 304 .

d. Determine the percentage of all samples of three Swedish men that have mean brain weights within 0.1kg of the population mean brain weight of 1.40kg. Interpret your answer in terms of sampling error.

e. Repeat part (d) for samples of size 12

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