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WorksheetsPractical 9 Task 1
Total questions: 10
Worksheet time: 26mins
Use Minitab to create a scatterplot for the data. What is the relationship between BMI and total cholesterol?
Positive
Negative
No relationship
Identify the variables used in this study.
Explanatory variable: BMI
Response variable: Total Cholesterol
Explanatory variable: Total Cholesterol
Response variable: BMI
Using Minitab, what is the equation of the least-squares regression line?
Conduct a test with the following hypotheses H0: β = 0 vs H1: β ≠ 0 to see if there is a linear relationship between Total Cholesterol and BMI. Assume α = 0.05.
What is the P-value? (Correct to 3 d.p.)
(a)
Conduct a test with the following hypotheses H0: β = 0 vs H1: β ≠ 0 to see if there is a linear relationship between total cholesterol and BMI. Assume α = 0.05.
Interpret the P-value obtained.
As P-value = 0.001 < α = 0.05, H0 is rejected. β is significantly different from 0. There is a significant linear relationship between BMI and total cholesterol.
As P-value = 0.001 < α = 0.05, H0 is rejected. ρ is significantly different from 0. There is a significant linear relationship between BMI and total cholesterol.
As P-value = 0.980 > α = 0.05, H0 is not rejected. ρ is not significantly different from 0. There is no significant linear relationship between BMI and total cholesterol.
As P-value = 0.183 > α = 0.05, H0 is not rejected. β is not significantly different from 0. There is no significant linear relationship between BMI and total cholesterol.
What is the slope of the regression line? Give your answer correct to 2 d.p.
(a)
Interpret the slope of the regression line.
For every 1 kg/m2 increase in BMI, a person’s total cholesterol increases by 7.65 mg/dL on average.
For every 1 mg/dL increase in total cholesterol, a person’s BMI increases by 7.65 kg/m2 on average.
For every 7.65 kg/m2 increase in BMI, a person’s total cholesterol increases by 1 mg/dL on average.
For every 7.65 mg/dL increase in total cholesterol, a person’s BMI increases by 1 kg/m2 on average.
Predict the total cholesterol for a person with BMI of 30.
229.5
230.6
235.9
Not applicable, as BMI of 30 is out of range of the data used to fit the model (extrapolation).
What is the value for R2? Give your answer correct to 1 d.p.
(a)
Use Minitab to generate the residual plot of the fitted model. What can you conclude?
The points are scattered randomly. The model is a good fit for the data.
The points are scattered randomly. The model is not a good fit for the data.
The points shows a positive relationship between BMI and total cholesterol. The model is a good fit for the data.
The points are scattered randomly. There is no relationship between BMI and total cholesterol.
