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Date May 2021 Marks available 2 Reference code 21M.1.AHL.TZ1.14
Level Additional Higher Level Paper Paper 1 Time zone Time zone 1
Command term Find Question number 14 Adapted from N/A

Question

The weights of apples from Tony’s farm follow a normal distribution with mean 158 g and standard deviation 13 g. The apples are sold in bags that contain six apples.

Find the mean weight of a bag of apples.

[2]
a.

Find the standard deviation of the weights of these bags of apples.

[2]
b.

Find the probability that a bag selected at random weighs more than 1kg.

[2]
c.

Markscheme

158×6=948g           (M1)A1


[2 marks]

a.

variance 6×132           (M1)

SD=31.8g  136, 31.8433           A1


[2 marks]

b.

X~N948, 31.84332

PX>1000=0.0512   0.0512350           (M1)A1


Note: Accept 0.0510 0.0510014 if 3 sf value 31.8 is used.
Award (M1)A1FT if the answer is correct for their SD, even if no working is shown. e.g. If the SD is 78 then accept 0.252.


[2 marks]

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Topic 4—Statistics and probability » SL 4.9—Normal distribution and calculations
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