From a sample of ten towns in the North East of England data on male unemployment and car ownership was obtained. This data is presented in the following table:
(i) Construct a scatter diagram of this data and describe the relationship.
(ii) Calculate the correlation coefficient and comment.
(iii) Determine the regression line and draw this on your scatter diagram.
(iv) Use the regression line to predict y when x = 7 per cent and provide a 95 per cent prediction interval. (v) Comment on how well the regression line fits the data.
Q6
Costs of production have been monitored for some time within a company and the following data found:
a. Construct a scatter diagram for the data.
b. Calculate the coefficient of determination and explain its significance for the company.
c. Is there a better model than the simple linear relationship that would fit this data? If your answer is 'yes':
1. Calculate the new coefficient of determination.
2. Determine the regression line and place the line on the scatter diagram.