Page 86 - Math SL HB Sem 3
P. 86
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[Maximum mark: B]
, A random variable X is distributed normally with a mean of 20 and variance 9.
l?
(a) Find P(X <24.5). [3 marks]
(b) Let P(X<t)=0.85.
(i) Represent this information on the following diagram.
20
(ii) Find the value of &. [5 marks]
I 1 /5A4,,\TME/SPAENG I' I' Z2 IXX
It1. [Maximum mark: 7]
Let the randorn variable X be normally distributed with mean 25- as shown in the
following diagram.
25 21
The shaded region between 25 and 27 represenrs 30 % olthe distribution.
(a) Find P(X > 27).
[2 marks]
(b) Find the standard deviation of X.
l5 ntarksJ
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