An experiment was conducted into car tyre wear by the department of Materials Science at Lowlands University, which it has been asked to carry out by a tyre company. The tyre company hascreated a new compound which it hopes will make tyres last much longer. Various levels of the compound were mixed in with rubber to make tyres. Apart from that, all the tyres were identical, with 16mm of tread when new. One hundred motorists chosen at random were given new tyres, and split into ten groups. After each motorist had completed 10,000 miles on the new tyres, the level of tread remaining was measured. The data recording the experiment is set out in the table below. You have been asked to use correlation analysis to see if there is a relationship between the percentage of the new compound and the wear on the tyres. Identify appropriate x and y variables, stating clearly which variable is the “x” variable and which is the “y” variable and why you have chosen that arrangement. Calculate (using any method you choose) the correlation coefficient and show your working out in full. When you have calculated the correlation coefficient, explain IN YOUR OWN WORDS what its value tells us. Group of motorists % of new compound Average mm of tread remaining 1 5 8 2 5.5 8.4 3 6 8.6 4 6.5 8.8 5 7 9 6 7.5 9.2 7 8 9.4 8 8.5 9.3 9 9 9.2 10 9.5 9.1 QUESTION 3 Is there anything else about the experiment in Question 2 which would cast doubt on the reliability of any conclusions drawn from it? Explain what and wh
urgently please answer question 2 and 3
QUESTION 2
An experiment was conducted into car tyre wear by the department of Materials Science at Lowlands University, which it has been asked to carry out by a tyre company.
The tyre company hascreated a new compound which it hopes will make tyres last much longer. Various levels of the compound were mixed in with rubber to make tyres. Apart from that, all the tyres were identical, with 16mm of tread when new. One hundred motorists chosen at random were given new tyres, and split into ten groups. After each motorist had completed 10,000 miles on the new tyres, the level of tread remaining was measured. The data recording the experiment is set out in the table below.
You have been asked to use
Identify appropriate x and y variables, stating clearly which variable is the “x” variable and which is the “y” variable and why you have chosen that arrangement.
Calculate (using any method you choose) the
When you have calculated the correlation coefficient, explain IN YOUR OWN WORDS what its value tells us.
|
Group of motorists |
% of new compound |
Average mm of tread remaining |
|
1 |
5 |
8 |
|
2 |
5.5 |
8.4 |
|
3 |
6 |
8.6 |
|
4 |
6.5 |
8.8 |
|
5 |
7 |
9 |
|
6 |
7.5 |
9.2 |
|
7 |
8 |
9.4 |
|
8 |
8.5 |
9.3 |
|
9 |
9 |
9.2 |
|
10 |
9.5 |
9.1 |
QUESTION 3
Is there anything else about the experiment in Question 2 which would cast doubt on the reliability of any conclusions drawn from it? Explain what and why.
Step by step
Solved in 2 steps
