Mathematics (AS & A Level) · May / June 2025 · Paper 65 · Question 5
9709
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Candidates for a certain diploma take two tests. Their marks for the first test and the second test are modelled by the independent variables with distributions ( . , . ) 38 1 3 8 N 2 and ( . , . ) 64 0 6 1 N 2 respectively. The final mark, F, for each candidate is found by doubling the mark in the first test and adding the result to the mark in the second test. Find the probability that the mean, F , of the final marks of a random sample of 25 candidates is greater than 143. [5]
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