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Date November 2014 Marks available 2 Reference code 14N.1.sl.TZ0.12
Level SL only Paper 1 Time zone TZ0
Command term Calculate Question number 12 Adapted from N/A

Question

The daily January temperature of Cairns is normally distributed with a mean of 34°C and a standard deviation of 3.

Calculate the probability that the temperature on a randomly chosen day in January is less than 39°C.

[2]
a.

Calculate the expected number of days in January that the temperature will be more than 39°C.

[2]
b.

On a randomly chosen day in January, the probability that the temperature is above T °C is 0.7.

Find the value of T.

[2]
c.

Markscheme

     (M1)

 

Note: Award (M1) for correctly shaded area.

 

0.952 (95.2%, 0.952209)     (A1)     (C2)

a.

31×(10.952209)     (M1)

Note: Award (M1) for multiplying 31 by (1 their answer to part (a)).

 

=1.48 (1.48150)     (A1)(ft)     (C2)

Note: Follow through from part (a).

b.

     (M1)

 

Note: Award (M1) for correctly shaded area.

32.4 (32.4267)     (A1)     (C2)

c.

Examiners report

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

Syllabus sections

Topic 4 - Statistical applications » 4.1 » The normal distribution.
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