Questions: Complete the statement. Round your answer to the nearest thousandth.
In a population that is normally distributed with mean 29 and standard deviation 3, the top 31% of the values are those greater than .
Transcript text: Complete the statement. Round your answer to the nearest thousandth.
In a population that is normally distributed with mean 29 and standard deviation 3, the top $31 \%$ of the values are those greater than $\square$ .
Solution
Solution Steps
Step 1: Determine the Z-Score for the 69th Percentile
To find the value above which the top \(31\%\) of the values lie, we first need to calculate the z-score corresponding to the \(69\)th percentile of the normal distribution. The z-score is given by:
\[
z = 0.4959
\]
Step 2: Convert the Z-Score to the Actual Value
Next, we convert the z-score to the actual value in the distribution using the formula:
\[
X = \mu + z \cdot \sigma
\]
where:
\(\mu = 29\) (mean)
\(\sigma = 3\) (standard deviation)
Substituting the values, we have:
\[
X = 29 + 0.4959 \cdot 3
\]
Calculating this gives:
\[
X = 29 + 1.4877 = 30.4877
\]
Rounding to the nearest thousandth, we find:
\[
X \approx 30.488
\]
Final Answer
The value above which the top \(31\%\) of the values lie is