Holooly Plus Logo

Question 29.22: A random variable, h, has a normal distribution with mean 7 ......

A random variable, h, has a normal distribution with mean 7 and standard deviation 2. Calculate the probability that

(a) h > 9         (b) h < 6          (c) 5 < h < 8

Step-by-Step
The 'Blue Check Mark' means that this solution was answered by an expert.
Learn more on how do we answer questions.

(a) Applying the transformation gives

9\to{\frac{9-7}{2}}=1

So h > 9 has the same probability as x > 1, where x is a random variable with a standard normal distribution:

P(h > 9) = P(x > 1) = 1 − P(x < 1) = 1 − 0.8413 = 0.1587

(b) Applying the transformation gives

6\rightarrow{\frac{6-7}{2}}=-0.5

So h < 6 has the same probability as x < −0.5:

P(x < −0.5) = P(x > 0.5) = 1 − P(x < 0.5) = 0.3085

(c) Applying the transformation to 5 and 8 gives

5\rightarrow{\frac{5-7}{2}}=-1\;\;\;\;\;\;\;8\rightarrow{\frac{8-7}{2}}=0.5

and so we require P(−1 < x < 0.5). Therefore
P(x < 0.5) = 0.6915            P(x < −1) = 0.1587

and then
P(−1 < x < 0.5) = 0.6915 − 0.1587 = 0.5328

 

Related Answered Questions

Question: 29.3

Verified Answer:

{\overline{{x}}}={\frac{-2.3+0+1+0.7}{4}}={...
Question: 29.5

Verified Answer:

(a)  x_{1}=-1,x_{2}=0,x_{3}=1.  Cle...
Question: 29.7

Verified Answer:

\textstyle\sum x_{i}^{2}=(-2)^{2}+(7.2)^{2}...
Question: 29.6

Verified Answer:

x_{1}=-2,x_{2}=7.2,x_{3}=6.9,x_{4}=-10.4,x_...
Question: 29.9

Verified Answer:

\mu=\int_{1}^{4}x\frac{1}{2\sqrt{x}}\,\math...