Unknown probabilities in a points distribution, a probability over an interval and the expected score

Unknown probabilities in a points distribution, a probability over an interval and the expected score

6 marks

At a school fair, a player throws a beanbag at a target and scores \(Y\) points. The probability distribution of \(Y\) is given in the table below, where \(k\) is a constant.

\(y\)\(0\)\(2\)\(3\)\(5\)
\(\mathrm{P}(Y=y)\)\(0.3\)\(k\)\(2k\)\(0.1\)
  1. Find the value of \(k\).[2]
  2. Find \(\mathrm{P}(1<Y\leq4)\).[2]
  3. Find the expected score, \(\mathrm{E}(Y)\).[2]

Solution:

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Answer:(a) \(k=0.2\) (b) \(0.6\) (c) \(\mathrm{E}(Y)=2.1\)

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