Question 1 Report
| Scores | 1 | 2 | 3 | 4 | 5 | 6 |
| Frequency | 2 | 5 | 13 | 11 | 9 | 10 |
The table shows the distribution of outcomes when a die is thrown 50 times. Calculate the :
(a) Mean deviation of the distribution ; (b) probability that a score selected at random is at least a 4.
(a) Mean deviation. First find the mean.
| Score (x) | 1 | 2 | 3 | 4 | 5 | 6 | Total |
|---|---|---|---|---|---|---|---|
| Freq (f) | 2 | 5 | 13 | 11 | 9 | 10 | 50 |
| fx | 2 | 10 | 39 | 44 | 45 | 60 | 200 |
| x | \(|x-\bar{x}|\) | \(f|x-\bar{x}|\) |
|---|---|---|
| 1 | 3 | 6 |
| 2 | 2 | 10 |
| 3 | 1 | 13 |
| 4 | 0 | 0 |
| 5 | 1 | 9 |
| 6 | 2 | 20 |
| Total | 58 |
(b) Probability of at least a 4. Scores 4, 5 or 6:
\[P(\ge 4) = \frac{11 + 9 + 10}{50} = \frac{30}{50} = \frac{3}{5} = 0.6\]Everything you need to excel in your exams