Question 4 - A-Level Maths

Exam Board	Edexcel
Module	S1 (Statistics 1)
Year	2022
Session	October
Topic	Discrete Probability Distributions
Type	Calculate E(X) from cumulative distribution

The cumulative distribution function of the discrete random variable $W$, which takes only the values 6,7 and 8 , is given by

$$F ( W ) = \frac { ( w + 3 ) ( w - 1 ) } { 77 } \text { for } w = 6,7,8$$ Find $\mathrm { E } ( W )$

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