53.4k views
1 vote
Assume the random variable X is normally distributed, with mean μ = 52 and standard deviation σ = 4. Find the 9th percentile.

User Sparkymat
by
7.8k points

1 Answer

5 votes

Final answer:

To find the 9th percentile, you can use the Z-score formula. The Z-score is calculated by subtracting the mean from the given value and then dividing by the standard deviation. For this question, the 9th percentile of the normally distributed random variable X is approximately 46.64.

Step-by-step explanation:

To find the 9th percentile, we can use the Z-score formula. The Z-score is calculated by subtracting the mean from the given value and then dividing by the standard deviation. For the 9th percentile, we need to find the Z-score that corresponds to a cumulative probability of 0.09. Using a standard normal distribution table or calculator, we find that the Z-score is approximately -1.34.

Next, we can use the Z-score formula to find the corresponding value at the 9th percentile.

Z = (X - μ) / σ

-1.34 = (X - 52) / 4

Solving for X:

-1.34 * 4 = X - 52

-5.36 = X - 52

X = 52 - 5.36

X ≈ 46.64

Therefore, the 9th percentile of the normally distributed random variable X is approximately 46.64.

User Uelordi
by
8.8k points