3. A group of 60 children were each asked to choose an integer value between 1 and 9 inclusive. Their choices are summarised in the table below.
| Value chosen | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| Number of children | 3 | 4 | 5 | 10 | 12 | 13 | 7 | 4 | 2 |
- Calculate the mean and standard deviation of the values chosen.
It is suggested that the value chosen could be modelled by a discrete uniform distribution.
- Write down the mean that this model would predict.
Given also that the standard deviation according to this model would be 2.58,
- explain why this model is not suitable and suggest why this is the case.