Question

directions answer the questions below to check your understanding and move forward in the course! this quiz is not graded. given the mean score of an iq test is 100 with a standard deviation of 10, what is the probability that a person would score lower than 90? select the correct answer 13.5% 34% 50% 16%

Explanation:

Step1: Calculate the z - score

The formula for the z - score is $z=\frac{x-\mu}{\sigma}$, where $x = 90$, $\mu=100$, and $\sigma = 10$. So, $z=\frac{90 - 100}{10}=\frac{- 10}{10}=-1$.

Step2: Use the standard normal distribution table

The standard normal distribution table gives the cumulative probability for a given z - score. For $z=-1$, the cumulative probability $P(Z < - 1)$ is $0.1587$ or $15.87\%\approx16\%$.

Answer:

$16\%$