- [Maximum mark: 7]
The scores on a test, out of 7 points, for 220 students are shown in the following table.
| Score | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Frequency | 11 | 24 | 26 | 35 | 61 | 43 | 20 |
(a) Find the mean and standard deviation of these test scores. Give your answers correct to four significant figures. [3]
(b) The scores are multiplied by ten. Write down the new mean and standard deviation. [2]
(c) After the scores have been multiplied by ten, 30 points are added to each of them. Write down the new mean and standard deviation. [2]