Question
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In a certain school district in a large metropolitan area, the SAT scores over that past five
years are normally distributed with a mean of 1489. Furthermore, is 1297 . What is the
score for this population?

(Enter answer rounded to the nearest whole number.)

Ask by Willis Kelley. in the United States
Mar 18,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

The score is approximately 1958.

Solution

To find the score for the SAT scores in this population, we need to follow these steps:
  1. Understand the distribution: The SAT scores are normally distributed with a mean ( ) of 1489. We also know that the first quartile ( ) is 1297.
  2. Find the standard deviation: Since we have , we can use it to find the standard deviation ( ). In a normal distribution, corresponds to the 25th percentile. We can use the z-score for the 25th percentile to find .
    The z-score for the 25th percentile is approximately -0.674. The formula for is:
    Plugging in the values:
  3. Solve for :
    Rearranging the equation gives:
  4. Calculate :
    Now, let’s calculate .
  5. Find : The z-score for the 95th percentile is approximately 1.645. We can use the formula:
Now, let’s perform the calculations.
First, we will calculate and then use it to find .
Calculate the value by following steps:
  • step0: Calculate:
  • step1: Convert the expressions:
  • step2: Multiply by the reciprocal:
  • step3: Multiply:
  • step4: Multiply:

    Calculate or simplify the expression .
    Calculate the value by following steps:
  • step0: Calculate:
  • step1: Divide the numbers:
  • step2: Multiply the numbers:
  • step3: Reduce fractions to a common denominator:
  • step4: Transform the expression:
  • step5: Multiply the numbers:
  • step6: Add the numbers:
  1. Calculate the standard deviation ( ):
  2. Calculate the score:
Now, rounding to the nearest whole number gives us:
Thus, the score for this population is 1958.

Answered by UpStudy AI and reviewed by a Professional Tutor

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Simplify this solution

Bonus Knowledge

To find for this normally distributed population, we first need the standard deviation ( ). Since we have the first quartile ( ), we can use it to estimate the standard deviation. In a normal distribution, corresponds to the 25th percentile.
Using the z-score for the 25th percentile, which is approximately -0.674, we can set up the equation:
Substituting the known values:
Now, solve for :
Now that we have , we can find using the z-score for the 95th percentile, which is approximately 1.645:
Rounding to the nearest whole number gives us:
Now for , we use the z-score for the 5th percentile, which is approximately -1.645:
Rounding to the nearest whole number gives:
Therefore, is 1021.

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