Question
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.)
years are normally distributed with a mean of 1489. Furthermore,
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:
-
Understand the distribution: The SAT scores are normally distributed with a mean (
) of 1489. We also know that the first quartile ( ) is 1297. -
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 foris: Plugging in the values: -
Solve for
:
Rearranging the equation gives: -
Calculate
:
Now, let’s calculate. -
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:
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:
-
Calculate the standard deviation (
): -
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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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.