Answer:
P 81 = 73.5
Step-by-step explanation:
This is a normal distribution problem with a mean of 63.2 and standard deviation of 11.7.
Let the number that separates the bottom 81% from the top 19% be x' and let it's z-score be z'.
P(x ≤ x') = P(z ≤ z') = 0.81
Using the normal distribution table,
z' = 0.878
But note that the z-score for any value is that value minus the mean divided by standard deviation.
z' = (x' - μ)/σ
0.878 = (x' - 63.2)/11.7
x' = 73.4726 = 73.5 to 1 d.p
Hope this Helps!!!
