Q304 · Practice questionTechnology-freeComplex familiar6 marks
QUESTION 304 (6 marks)
A random variable has density for , and zero otherwise.
a)[1 mark]
Determine .
b)[3 marks]
Determine and exactly.
c)[2 marks]
Determine the median exactly.
WORKED SOLUTION
6 marksPractice marking scheme
ANSWER
a) . b) , . c) .
Worked solution
a) , so .
b) ; . Variance is .
c) The median satisfies , so .
Exact answers unless rounding is specified; equivalent forms accepted.
a) Normalises the density.
b) Determines the mean.
b) Determines the second moment.
b) Determines the variance.
c) Sets the cumulative probability equal to 1/2.
c) Solves for the exact median.
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