The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. You enrolled in a class of 25 students. What is the probability that the class' average IQ exceeds 130?

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Answer:

The required probability is 0.0228

Step-by-step explanation:

Consider the provided information.

Mean of 100 and a standard deviation of 15. You enrolled in a class of 25 students.

Therefore, [tex]\mu =100,\sigma 15[/tex]

We want the probability that the class' average IQ exceeds 130

As we know: [tex]z=\frac{\bar x -\mu}{\sigma}[/tex]

Substitute the respective value as shown:

[tex]z=\frac{130 -100}{15}[/tex]

[tex]z=\frac{30}{15}[/tex]

[tex]z=2[/tex]

[tex]P(z>2)=1-P(z<2)[/tex]

Now by using z table:

[tex]P(x>130)=P(z>2)=1-0.9772 [/tex]

[tex]P(x>130)=0.0228 [/tex]

Hence, the required probability is 0.0228