Question

EC[max score=100] If you know that for a normal distribution, x=70 is at the 45th percentile & standard distribution = 10. Whats the mean?

Answer 1

Solution:
Given in the question
Population standard deviation () = 10
45th percentile is 70 i.e.
X = 70 and p-value = 0.45
From Z table we found Z-score = -0.12566
So Z-score can be calculated as
Z-score = (X-mean)/
So mean can be calculated as
Mean = X - Z-score *
Mean = 70 - (-0.12566*10) = 70 + 1.2566 = 71.2566 or 71.26
Mean = 71.26