Analysis and Approaches for IBDP Maths Ebook 1 | Page 259

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2. The following table shows the probability distribution of a discrete random variable X .
x 0 20 40 60
1 1 2
P( X � x)
k
10 5 5
(a) Find the value of k .
(b) Find E( X ) .
[3]
[3]
3. The following table shows the probability distribution of a discrete random variable X .
It is given that k � 0 .
x 1 2 k
2
1 4
P( X � x)
k
14 14 14
(a) Find the value of k .
(b) Find E( X ) .
4. The following table shows the probability distribution of a discrete random variable X .
[3]
[3]
19
x k k � 1 k � 2 8
k 1 k 1
P( X � x)
2 8 4 8
(a) Find the value of k .
(b) Find E( X ) .
[3]
[3]
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