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.
urgent please
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 has created 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
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 |
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