A normal population has mean \mu = 20 and standard deviation \sigma = 4. What proportion of the population is less than 18?

cistG

cistG

Answered question

2020-10-25

A normal population has mean μ=20 and standard deviation σ=4.
What proportion of the population is less than 18?

Answer & Explanation

sovienesY

sovienesY

Skilled2020-10-26Added 89 answers

Step 1
According to the given data,
Mean (μ)=20
Standard deviation (σ)=4
XN(20,4)
Step 2
The required percentage of the population that is under 18 can be found as:
P(X<18)=P(xμσ<18204)
=P(Z<0.5)=0.3085 (Using standard normal table)
Thus, the required proportion is 0.3085.

Jeffrey Jordon

Jeffrey Jordon

Expert2021-11-17Added 2605 answers

Answer is given below (on video)

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