The following exercises are based on the following sample data consisting of numbers of enrolled students (in thousands) and numbers of burglaries for randomly selected large colleges in a recent year (based on data from the New York Times).

Conclusion The linear correlation coefficient r is found to be 0.499, the P-value is 0.393, and the critical values for a 0.05 significance level are\( \pm 0.878\). What should you conclude?

Short Answer

Expert verified

There is no evidence to conclude that there is a significant linear relationship between the number of enrolment and burglaries at 0.05 significance level.

Step by step solution

01

Given information

For the two variables, enrolment, and burglaries,

Correlation coefficient (r) is 0.499 with associated P-value as 0.393.

Critical values are -0.878 and 0.878 at 0.05 level of significance.

02

Identify the hypothesis

Here\(\rho \)represents the population correlation coefficient.

\(\begin{array}{l}{H_0}:\rho = 0\\{H_1}:\rho \ne 0\end{array}\)

03

State the decision rule

Comparing the P-value and significance level,

If\(P - value < \alpha \), reject the null hypothesis.

Thus, it can be concluded that there is a significant linear relationship between the two variables.

If\(P - value > \alpha \), fail to reject the null hypothesis.

Thus, it can be concluded that there is nosignificant linear relationship between the two variables.

Asimilar result can be concluded using critical values.

  • If the correlation coefficient value lies between critical values, the result for correlation coefficient is insignificant.
  • If the correlation coefficient value does lie between critical values, the result for correlation coefficient is significant.
04

Step 4:State the conclusion for the correlation coefficient

Here\(P - value = 0.393\)and\(\alpha = 0.05\).

As\(P - value > 0.05\), wefail to reject the null hypothesis.

In a similar way, 0.499 lies between -0.878 and 0.878, which leads to the rejection of null hypothesis.

Thus, it can be concluded that there is not enough evidence fora significant linear correlation between enrolment and burglaries.

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The following exercises are based on the following sample data consisting of numbers of enrolled students (in thousands) and numbers of burglaries for randomly selected large colleges in a recent year (based on data from the New York Times).

The sample data result in a linear correlation coefficient of r= 0.499 and the regression equation\(\hat y = 3.83 + 2.39x\). What is the best predicted number of burglaries, given an enrollment of 50 (thousand), and how was it found?

Critical Thinking: Is the pain medicine Duragesic effective in reducing pain? Listed below are measures of pain intensity before and after using the drug Duragesic (fentanyl) (based on data from Janssen Pharmaceutical Products, L.P.). The data are listed in order by row, and corresponding measures are from the same subject before and after treatment. For example, the first subject had a measure of 1.2 before treatment and a measure of 0.4 after treatment. Each pair of measurements is from one subject, and the intensity of pain was measured using the standard visual analog score. A higher score corresponds to higher pain intensity.

Pain Intensity Before Duragesic Treatment

1.2

1.3

1.5

1.6

8

3.4

3.5

2.8

2.6

2.2

3

7.1

2.3

2.1

3.4

6.4

5

4.2

2.8

3.9

5.2

6.9

6.9

5

5.5

6

5.5

8.6

9.4

10

7.6










Pain Intensity After Duragesic Treatment

0.4

1.4

1.8

2.9

6

1.4

0.7

3.9

0.9

1.8

0.9

9.3

8

6.8

2.3

0.4

0.7

1.2

4.5

2

1.6

2

2

6.8

6.6

4.1

4.6

2.9

5.4

4.8

4.1










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What is the relationship between the linear correlation coefficient rand the slope\({b_1}\)of a regression line?

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