a marketing company conducted a survey to assess the audience response to different aspects of a new…

a marketing company conducted a survey to assess the audience response to different aspects of a new advertisement. the company randomly chose 100 people to watch several advertisements of different lengths. the respondents were asked to note which ads they disliked. the table shows the survey results.\n| duration of ad (seconds) | number of viewers who disliked ad |\n| ---- | ---- |\n| 18 | 24 |\n| 22 | 32 |\n| 26 | 30 |\n| 30 | 41 |\n| 34 | 32 |\n| 38 | 45 |\n| 42 | 31 |\n| 46 | 38 |\n| 50 | 41 |\n| 54 | 52 |\n| 60 | 62 |\nthe correlation coefficient for this data set is close to . based on this information, we can conclude that there is a relationship between the duration of advertisements and the audience disliking them.
Answer
Explanation:
Step1: Recall correlation - coefficient formula
The formula for the correlation coefficient $r$ is $r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^{2}-(\sum x)^{2}][n\sum y^{2}-(\sum y)^{2}]}}$, where $n$ is the number of data - points, $x$ is the duration of the ad, and $y$ is the number of viewers who disliked the ad. Let $x$ be the duration of the ad (in seconds) and $y$ be the number of viewers who disliked the ad. First, calculate the following sums for $n = 12$ data - points:
| $x$ | $y$ | $xy$ | $x^{2}$ | $y^{2}$ |
|---|---|---|---|---|
| 18 | 24 | 432 | 324 | 576 |
| 22 | 32 | 704 | 484 | 1024 |
| 26 | 30 | 780 | 676 | 900 |
| 30 | 41 | 1230 | 900 | 1681 |
| 34 | 32 | 1088 | 1156 | 1024 |
| 38 | 45 | 1710 | 1444 | 2025 |
| 42 | 31 | 1302 | 1764 | 961 |
| 46 | 38 | 1748 | 2116 | 1444 |
| 50 | 41 | 2050 | 2500 | 1681 |
| 54 | 52 | 2808 | 2916 | 2704 |
| 60 | 62 | 3720 | 3600 | 3844 |
| $\sum x=420$ | $\sum y = 438$ | $\sum xy=17672$ | $\sum x^{2}=18880$ | $\sum y^{2}=18865$ |
Step2: Calculate the numerator
$n(\sum xy)-(\sum x)(\sum y)=12\times17672 - 420\times438$ $=212064-183960 = 28104$
Step3: Calculate the first part of the denominator
$n\sum x^{2}-(\sum x)^{2}=12\times18880-420^{2}$ $=226560 - 176400=50160$
Step4: Calculate the second part of the denominator
$n\sum y^{2}-(\sum y)^{2}=12\times18865 - 438^{2}$ $=226380-191844 = 34536$
Step5: Calculate the denominator
$\sqrt{(n\sum x^{2}-(\sum x)^{2})(n\sum y^{2}-(\sum y)^{2})}=\sqrt{50160\times34536}$ $=\sqrt{1732209760}\approx41617.42$
Step6: Calculate the correlation coefficient
$r=\frac{28104}{41617.42}\approx0.675$
Since the correlation coefficient $r\approx0.675$ which is positive, we can conclude that there is a positive linear relationship between the duration of advertisements and the audience disliking them.
Answer:
The correlation coefficient for this data set is close to $0.675$. Based on this information, we can conclude that there is a positive linear relationship between the duration of advertisements and the audience disliking them.