Math Problem Statement
A random sample of 140 teams playing in major international team sporting competitions has been selected to study corporate sponsorship and subsequent sporting success. Some of the variables recorded for each team are listed below.
VariableDescription
subid
Subject ID
sex
sex of players
numSponsors
number of distinct corporate sponsors
percentWin
the percentage of international games won
A simple linear regression is run to answer the research question, ’What is the relation between the percentage of international games won and number of distinct corporate sponsors?’ The results of the analysis are reported below:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 38.2271 2.4433 15.6459 0
numSponsors 0.7093 0.0649 10.9362 0
Address the following questions, assuming as necessary that all test assumptions are verified.
What is the null hypothesis? Choose one among the following options:
a. The slope of the regression line is zero
b. There is a significant relation, linear or non-linear, between the two variables
c. The slope of the regression line is significantly different from zero
d. There is no relation whatsoever, linear or non-linear, between the two variables
e. The slope of the regression line is either positive or negative
f. The relation between the two variables is linear
Answer 1 Question 3 abcdef
From the test statistic as reported above, we can conclude that the estimated value of the slope is:
Answer 2 Question 3 10.94 times its standard error1.96 times its standard error1.96 times the population standard deviation10.94 times the population standard deviation
From the p-value as reported above, we can conclude that the decision of the test is:
Answer 3 Question 3 Accept H0Reject H0Do not accept H0Do not reject H0
What is the conclusion of the test?
Answer 4 Question 3 There is evidence of a linear relationship between these two variables.There is no evidence of a linear relationship between these two variables.
Solution
Let's address each question in turn based on the provided output of the simple linear regression analysis.
Question 1: What is the null hypothesis?
The null hypothesis in a simple linear regression tests whether the slope of the regression line (representing the relationship between the independent variable and the dependent variable) is zero. This implies that there is no linear relationship between the two variables.
- The correct option is:
a. The slope of the regression line is zero.
Question 2: From the test statistic as reported above, we can conclude that the estimated value of the slope is:
The test statistic is calculated as the estimated slope divided by its standard error. According to the output, the test statistic for numSponsors
is 10.9362. This means that the slope estimate is 10.9362 times its standard error (which is 0.7093 / 0.0649).
- The correct option is:
10.94 times its standard error.
Question 3: From the p-value as reported above, we can conclude that the decision of the test is:
The p-value is essentially zero (reported as 0), which is far below common significance levels such as 0.05 or 0.01. When the p-value is this small, we reject the null hypothesis, indicating that there is significant evidence against the null hypothesis.
- The correct option is:
Reject H0.
Question 4: What is the conclusion of the test?
Since we rejected the null hypothesis, we have evidence to suggest a significant relationship between the percentage of international games won (percentWin
) and the number of corporate sponsors (numSponsors
). The positive slope of 0.7093 also suggests that as the number of sponsors increases, the percentage of games won tends to increase.
- The correct option is:
There is evidence of a linear relationship between these two variables.
Summary
- Null Hypothesis: The slope of the regression line is zero.
- Slope Estimate: 10.94 times its standard error.
- Decision of the Test: Reject H0.
- Conclusion: There is evidence of a linear relationship between the number of sponsors and the percentage of games won.
Follow-up questions:
- What would happen if the p-value was larger than 0.05?
- How does the standard error of the slope affect the significance of the test?
- What is the implication of a positive slope in the context of corporate sponsorship and team success?
- Can we conclude causality from this regression analysis?
- How would adding more variables to the model affect the results?
Tip: Always ensure that the assumptions of linear regression (like normality of residuals and homoscedasticity) are met to trust the results of your analysis.
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Math Problem Analysis
Mathematical Concepts
Statistics
Linear Regression
Hypothesis Testing
Formulas
Simple Linear Regression: y = β0 + β1x
Test Statistic = β1 / SE(β1)
p-value calculation for hypothesis testing
Theorems
Null Hypothesis for Regression
Slope Interpretation in Regression
p-value Significance Testing
Suitable Grade Level
College level statistics or advanced high school (Grades 11-12)
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