3. A class of children are each asked to draw a line that they think is 10 cm long without using a ruler. The teacher models how many centimetres each child's line is longer than 10 cm by the random variable \(X\) and believes that \(X\) has the following probability density function: $$f ( x ) = \left\{ \begin{array} { l c } \frac { 1 } { 8 } , & - 4 \leq x \leq 4
0 , & \text { otherwise } \end{array} \right.$$

1. Write down the name of this distribution.
2. Define fully the cumulative distribution function \(\mathrm { F } ( x )\) of \(X\).
3. Calculate the proportion of children making an error of less than \(15 \%\) according to this model.
4. Give two reasons why this may not be a very suitable model.