A person must score in the upper 2% of the population on an IQ test to qualify for membership in Mensa, the international high IQ society. If IQ scores are normally distributed with a mean of 100 and a standard deviation of 15, what score must a person have to qualify for Mensa?

Respuesta :

Answer:

A person must score 131 or above to qualify for Mensa.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 100

Standard Deviation, σ = 15

We are given that the distribution of IQ score is a bell shaped distribution that is a normal distribution.

Formula:

[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]

We have to find the value of x such that the probability is 0.02

[tex]P( X > x) = P( z > \displaystyle\frac{x - 100}{15})=0.02[/tex]  

[tex]= 1 -P( z \leq \displaystyle\frac{x - 100}{15})=0.02[/tex]  

[tex]=P( z \leq \displaystyle\frac{x - 100}{15})=0.98[/tex]  

Calculation the value from standard normal z table, we have,  

[tex]P(z < 2.054) = 0.98[/tex]

[tex]\displaystyle\frac{x - 100}{15} = 2.054\\\\x = 130.81 \approx 131[/tex]

Thus, a person must score 131 or above to qualify for Mensa.