Mathematics 9709 · AS & A Level · The normal distribution
The normal distribution — practice question
The weights of the green apples sold by a shop follow a normal distribution with mean $90$ grams and standard deviation $8$ grams.
(a)[4]
Determine the probability that one randomly selected green apple has a mass between $83$ grams and $95$ grams.
(b)[5]
The shop also sells red apples. $60\%$ of the red apples sold by the shop weigh more than $80$ grams. $160$ red apples are selected at random from the shop. Use a suitable approximation to determine the probability that fewer than $105$ of the selected red apples weigh more than $80$ grams.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct standardisation to $P(-0.875<Z<0.625)$” …