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Question
The probability distribution of a discrete r.v.X is as follows.
| x | 1 | 2 | 3 | 4 | 5 | 6 |
| P(X = x) | k | 2k | 3k | 4k | 5k | 6k |
Complete the following activity.
Solution: Since `sum"p"_"i"` = 1
P(X ≥ 3) = `square - square - square = square`
Solution
Since `sum"p"_"i"` = 1
k + 2k + 3k + 5k + 6k = 1
∴ 21k = 1
∴ k = `1/21`
P(X ≥ 3) = 1 – P(X < 3)
= 1 – P(X = 1) – P(X = 2)
= 1 – k – 2k
= `1 - 1/21 - 2/21`
= `6/7`
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