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.
Calculate the expected number of days in January that the temperature will be more than 39°C.
On a randomly chosen day in January, the probability that the temperature is above T °C is 0.7.
Find the value of T.
Markscheme
(M1)
Note: Award (M1) for correctly shaded area.
0.952 (95.2%, 0.952209…) (A1) (C2)
31×(1−0.952209) (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).
(M1)
Note: Award (M1) for correctly shaded area.
32.4 (32.4267…) (A1) (C2)