In Exercises 7.3-7.10, we have given population data for a variable, For each exercise, do the following tasks.
a. Find the mean, μ, of the variable.
b. For each of the possible sample sizes, construct a table similar to Table 7.2 on page 293 and draw a dotplot for the sampling distribution of the sample mean similar to Fig. 7.l on page 293.
c. Construct a graph similar to Fig.7.3 and interpret your results.
d. For each of the possible sample sises. find the probability that the sample mean will equal the population mean.
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 (in magnitude), that is, that the absolute value of the difference between the sample mean and the population mean is at most 0.5.
7.3 Population data: 1,2,3.

Short Answer

Expert verified

(a) The mean, μ, of the variable is 2.

(b) A table is created, and the dot plot is created.

(c) The dot plot for the sample mean's sampling distribution as follows:

(d) The probability that sample mean will be equal to population mean for n=3is 1.

(e) The probability that X¯will be within 0.5or less of μfor n=3is 0.

Step by step solution

01

Part (a) Step 1: Given information

To find the mean, μ, of the variable.

02

Part (b) Step 1: Given information

To construct a table and draw a dotplot for the sampling distribution of the sample mean for each of the possible sample sizes.

03

Part (b) Step 2: Explanation

Create a table for each of the various sample sizes as follows:
If n=1is the sample size,

Sample
X
1
1.0
2
2.0
3
3.0

If n=2is the sample size,

Sample
X
1.2
1.5
1.3
2.0
2.3
2.5

If n=3is the sample size,

Sample
X
1,2,3
2
04

Part (b) Step 3: Explanation

As a result, the dot plot for the sampling distribution of the sample mean is constructed as shown below:

Hence, a table is created, and the dot plot is created.

05

Part (c) Step 1: Given information

To construct a graph similar to Fig. 7.3 and interpret the results.

06

Part (c) Step 2: Explanation

Let, the population data is 1,2,and 3.

Construct the dot plot for the sample mean's sampling distribution as follows:

Hence, the graph is constructed.

07

Part (d) Step 1: Given information

To find the probability that the sample mean will equal the population mean.

08

Part (d) Step 2:Explanation

Let, the population data is 1,2,and 3.
Find the probability that the sample mean will equal the population mean for each feasible sample size. Note that there is one dot corresponding to μ=2 in the dot lot.
The probability that sample mean will be equal to population mean=13
Correspondingly, the probability that the sample mean equals the population mean for n=2,
=13
As a result, the probability that sample mean will be equal to population mean for n=3is 1.

09

Part (e) Step 1: Given information

To find the probability that the sampling error made in estimating the population mean by the sample mean will be 0.5 or less.

10

Part (e) Step 2: Explanation

Let, the population data is 1,2,and 3.
Find the probability that the sampling error in calculating the population mean by the sample mean is 0.5or less; that is, the probability that Xis 0.5or less than μ.
For n=1and n=2, the number of dots within 0.5or less of μ=2 is one out of three.
Because there are no dots in the sample for n=3, the mean Xwill be within 0.5of μ.
Since, the probability that X¯will be within 0.5or less of μis for n=1is 13.

Correspondingly, the probability that X¯will be within 0.5less of μfor n=2is 13.

As a result, the probability that X¯will be within 0.5or less of μfor n=3is 0.

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Most popular questions from this chapter

7.42 NBA Champs. Repeat parts (b) and (c) of Exercise7.41 for samples of size 1. For part (b), use your answer to Exercise7.12(b).

Refer to Exercise 7.5 on page 295.

a. Use your answers from Exercise 7.5(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, μs, of the variable x¯, using only your answer from Exercise 7.5(a).

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a. Use the answer you obtained in Problem 5(b)and Definition 3.11on page 140 to find the mean of the variable x^Interpret your answer.

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Menopause in Mexico. In the article "Age at Menopause in Puebla. Mexico" (Human Biology, Vol. 75, No, 2, Pp. 205-206), authors L. Sievert and S. Hautaniemi compared the age of menopause for different populations. Menopause, the last menstrual period, is a universal phenomenon among females. According to the article, the mean age of menopause, surgical or natural, in Puebla, Mexico is 44.8 years with a standard deviation of 5.87 years. Letx¯ denote the mean age of menopause for a sample of females in Puebla, Mexico.
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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.

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