Chapter 4, Problem 12CR

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8th Edition

Charles Henry Brase + 1 other

ISBN: 9781337558075

Textbook Problem

In Problems 9-14,

(a) Draw a scatter diagram for the data.

(b) Find

(c) Find the sample correlation coefficient *r* and the coefficient of determination
*y* is explained by the least-squares model?

**Sales: Insurance** Dorothy Kelly sells life insurance for the Prudence Insurance Company. She sells insurance by making visits to her clients' homes. Dorothy believes that the number of sales should depend, to some degree, on the number of visits made. For the past several years, she has kept careful records of the number of visits (*x)* she makes each week and the number of people (*y*) who buy insurance that week. For a random sample of 15 such weeks, the *x* and *y* values follow:

X |
11 | 19 | 16 | 13 | 28 | 5 | 20 | 14 | 22 | 7 | 15 | 29 | 8 | 25 | 16 |

y |
3 | 11 | 8 | 5 | 8 | 2 | 5 | 6 | 8 | 3 | 5 | 10 | 6 | 10 | 7 |

Complete parts (a) through (c). given

**(a)**

To determine

**To graph:** The scatter diagram.

Explanation

**Given:** The data which consists of variables, â€˜number of visits in a weekâ€™ and â€˜number of people who buy insurance that weekâ€™, represented by *x* and *y*, respectively, is provided.

**Graph:**

Follow the steps given below in Excel to obtain the scatter diagram of the data.

Step 1: Enter the data into Excel sheet. The screenshot is given below.

Step 2: Select the data and click on â€˜Insertâ€™. Go to charts and select the chart type â€˜Scatterâ€™.

**(b)**

To determine

**To find:** The values of *b,* and the equation for the least-squares line.

**(c)**

To determine

The values of *r* and *y* that can be explained by the least-squares model.

**(d)**

To determine

**To find:** The least-squares line forecast for *y* at

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Sect-4.1 P-11PSect-4.1 P-12PSect-4.1 P-13PSect-4.1 P-14PSect-4.1 P-15PSect-4.1 P-16PSect-4.1 P-17PSect-4.1 P-18PSect-4.1 P-19PSect-4.1 P-20PSect-4.1 P-21PSect-4.1 P-22PSect-4.1 P-23PSect-4.2 P-1PSect-4.2 P-2PSect-4.2 P-3PSect-4.2 P-4PSect-4.2 P-5PSect-4.2 P-6PSect-4.2 P-7PSect-4.2 P-8PSect-4.2 P-9PSect-4.2 P-10PSect-4.2 P-11PSect-4.2 P-12PSect-4.2 P-13PSect-4.2 P-14PSect-4.2 P-15PSect-4.2 P-16PSect-4.2 P-17PSect-4.2 P-18PSect-4.2 P-19PSect-4.2 P-20PSect-4.2 P-22PSect-4.2 P-23PSect-4.2 P-24PSect-4.2 P-25PCh-4 P-1CRCh-4 P-2CRCh-4 P-3CRCh-4 P-4CRCh-4 P-5CRCh-4 P-6CRCh-4 P-7CRCh-4 P-8CRCh-4 P-9CRCh-4 P-10CRCh-4 P-11CRCh-4 P-12CRCh-4 P-13CRCh-4 P-14CRCh-4 P-1UTACh-4 P-2UTACh-4 P-3UTACh-4 P-4UTACh-4 P-5UTACh-4 P-6UTA

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