(a)[3]
Find the standard deviation for the weights of these apples.
(b)[4]
Find the probability that a randomly selected apple of this variety has a weight that is less than 4 grams away from the mean weight.
Mathematics 9709 · AS & A Level · The normal distribution
The normal distribution — practice question
For one variety of apples, the weights are normally distributed with mean 82 grams. 22% of the apples in this variety weigh more than 87 grams.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Proper standardisation $P(X>87)=P\left(Z>\frac{87-82}{\sigma}\right)$.” …
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