Assume IQ is normally distributed with mean 100 points and standard deviation 15 points. What percent of test takers score at least 70 points? Use the sketch area to show your work and enter your answer below.
To find the percentage of test takers who score at least 70 points on an IQ test, we need to calculate the area to the right of 70 points on the normal distribution curve.
First, we need to find the Z-score corresponding to 70 points.
Z = (X - μ) / σ
Z = (70 - 100) / 15
Z = -2
Next, we can use a Z-table or a calculator to find the percentage of test takers who score at least 70 points, which is equivalent to finding the area to the right of Z = -2.
From a standard normal distribution table, the area to the right of Z = -2 is approximately 0.9772.
Therefore, approximately 97.72% of test takers score at least 70 points on the IQ test.