CAIE FP2 2008 November — Question 9

Exam BoardCAIE
ModuleFP2 (Further Pure Mathematics 2)
Year2008
SessionNovember
TopicChi-squared distribution

9 A sample of 100 observations of the continuous random variable \(T\) was obtained and the values are summarised in the following table.
Interval\(1 \leqslant t < 1.5\)\(1.5 \leqslant t < 2\)\(2 \leqslant t < 2.5\)\(2.5 \leqslant t < 3\)
Frequency6417163
It is required to test the goodness of fit of the distribution with probability density function given by $$f ( t ) = \begin{cases} \frac { 9 } { 4 t ^ { 3 } } & 1 \leqslant t < 3
0 & \text { otherwise } \end{cases}$$ The relevant expected values are as follows.
Interval\(1 \leqslant t < 1.5\)\(1.5 \leqslant t < 2\)\(2 \leqslant t < 2.5\)\(2.5 \leqslant t < 3\)
Expected frequency62.521.87510.1255.5
Show how the expected value 10.125 is obtained. Carry out the test, at the \(10 \%\) significance level.