91Ó°ÊÓ

The given statement is:

The average age of a volunteer is about 28 years old. The following table reports the percentage of total volunteers serving by geographic region.

Africa:

$$\begin{gathered} 76×0.43=32.68 \\ ≈33 \end{gathered}$$

Latin America:

$$\begin{gathered} =76×0.21=15.96 \\ ≈16 \end{gathered}$$

Eastern Europe/ Central Asia:

$$\begin{gathered} 76×0.15=11.4 \\ ≈12 \end{gathered}$$

Asia:

$$\begin{gathered} 76×0.10=7.6 \\ ≈8 \end{gathered}$$

Caribbean:

$$\begin{gathered} 76×0.04=3.04 \\ ≈3 \end{gathered}$$

North Africa/Middle East:

$$\begin{gathered} 76×0.04=3.04 \\ ≈3 \end{gathered}$$

Pacific Islands:

$$\begin{gathered} 76×0.03=2.28 \\ ≈2 \end{gathered}$$

The sample size for the stratum "Africa":

$$\begin{gathered} 50×0.43=21.5 \\ ≈21 \end{gathered}$$

The sample size for the stratum "Latin America":

$$\begin{gathered} 50×0.21=10.5 \\ ≈11 \end{gathered}$$

The sample size for the stratum "Eastern Europe/ Central Asia":

$$\begin{gathered} 50×0.15=7.5 \\ ≈7 \end{gathered}$$

The sample size for the stratum "Asia":

$50×0.10=5$

The sample size for the stratum "Caribbean":

$50×0.04=2$

The sample size for the stratum "North Africa/Middle East":

$50×0.04=2$

The sample size for the stratum "Pacific Islands":

$$\begin{gathered} 50×0.3=1.5 \\ ≈2 \end{gathered}$$

Separate the population into strata (regions).

There are seven strata in this circumstance, with sizes of 33, 16, 12, 6, 3, 3, and 3.

Volunteers 1-33 make up stratum #1, whereas volunteers 34-48 make up stratum #2.

Volunteers in stratum #3 range from 49 to 60, volunteers in stratum #4 range from 61 to 66, volunteers in stratum #5 range from 67 to 70, volunteers in stratum #6 range from 71 to 73, and volunteers in stratum #7 range from 74 to 76.

For each stratum, create a basic random sample using the sample size specified in the table. To get 21 members from stratum #1, use MINITAB.

Procedure for MINITAB:

Step 1: Select Calc > Random Data > Integer from the menu bar.

Step 2: Double your selected sample size in the Number of rows of data to generate a section, just in case there are repeats. Set the sample size to 21.

Step 3: In the Store in the column, type Stratum 1 in column C1.

Step 4: Enter 1 as the minimum value.

Step 5: Enter 33 as the maximum value.

Step 6: Press the OK button.

MINITAB output

Stratum 1:

28 2 24 9 14 6 1 12 17 30 31 33 10 26 25 5 15 32 11 4 3.

Similarly, follow the MINITAB approach to find participants for each location.

Change the sample size, minimum value, and maximum value for each region in the MINITAB method.

Stratum 2:

36 38 43 35 37 47 39 40 46 41 48

Stratum 3:

57 49 58 50 52 51 54

Stratum 4:

65 64 62 66 63

Stratum 5:

69 70

Stratum 6:

71 73

Stratum 7:

75 76

Part (a) indicates that the number of volunteers to be chosen from the Caribbean is two.