The amount of Jen’s monthly phone bill is normally distributed with a mean of $50 and a standard deviation of $10. Find the 25th percentile.
A. About $46.30
B. About $43.30
C. About $43.40
D. about $43.20
Answer : B---43.30
agree
according to the chart I am using, I ge
43.26 , so I agree with your choice
To find the 25th percentile of Jen's monthly phone bill, we need to find the value below which 25% of the data falls.
Given that the phone bill follows a normal distribution with a mean of $50 and a standard deviation of $10, we can use the z-score formula to standardize the data. The z-score is calculated as:
z = (x - μ) / σ
Where:
x = value of interest
μ = population mean
σ = standard deviation
In this case, we need to find the z-score that corresponds to the 25th percentile, which can be written as z = -0.674 (lookup value in a standard normal distribution table).
Solving for x:
-0.674 = (x - 50) / 10
Rearranging the equation:
-0.674 * 10 = x - 50
-6.74 = x - 50
Adding 50 to both sides:
x = 50 - 6.74
x ≈ 43.26
So, the 25th percentile of Jen's monthly phone bill is approximately $43.26.
Now, we need to select the closest option from the given choices:
A. About $46.30
B. About $43.30
C. About $43.40
D. About $43.20
Among the given options, option B, about $43.30, is the closest to $43.26. Therefore, the correct answer is B.