Problem

The College Board reported that SAT scores in the early 2000 s were normally distributed with mean 1026 and standard deviation 210 . Refer to the table of values $\triangle$ Area Under the Standard Normal Distribution as needed. Part 1 of 2 (a) What percent of students scored over $606 ?$ $97.7 \%$ of students scored over 606 . (Round to the nearest tenth of a percent.) Part: $1 / 2$ Part 2 of 2 (b) Out of every 500 students, how many scored between 606 and 1446 ? We expect about SAT scores between 606 and 1446 .

Solution

Step 1 :Find the z-scores for 606 and 1446 using the formula \(z = \frac{x - \mu}{\sigma}\), where \(x\) is the score, \(\mu\) is the mean, and \(\sigma\) is the standard deviation.

Step 2 :Calculate the z-scores: \(z_1 = \frac{606 - 1026}{210} = -2.0\) and \(z_2 = \frac{1446 - 1026}{210} = 2.0\)

Step 3 :Use the standard normal distribution table to find the percentage of students who scored above 606: \(P(z > -2.0) = 0.9772\)

Step 4 :Calculate the percentage of students who scored between 606 and 1446: \(P(-2.0 < z < 2.0) = 0.9772 - 0.0228 = 0.9544\)

Step 5 :Find the number of students out of 500 who scored between 606 and 1446: \(500 \times 0.9544 = 477.2\)

Step 6 :\(\boxed{\text{(a) 97.7\% of students scored over 606.}}\)

Step 7 :\(\boxed{\text{(b) We expect about 477 students to have SAT scores between 606 and 1446 out of every 500 students.}}\)

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