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master cherundo
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Homework Statement
In an ancient culture, the average male life span was 37.6 years, with a standard deviation of 4.8 years The average female life span was 41.2 years, with a standard deviation of 7.7 years. use the properties of the normal distribution to find the following:
a. What percentage of men died before age 30?
b. What percentage of women lived to an age of at least 50?
c. At what age is a female death at the same relative position in the distribution as a male death at age 35?
Homework Equations
[tex]X'=s'z+\overline{X}[/tex]
using Standard Normal Distribution table to find percentile rank
The Attempt at a Solution
Problem a a is clear for me, but I have a little doubt in b, because
I am confused about choosing between [tex]PR_{49.9}[/tex] or [tex]PR_{50}[/tex]? Percentile rank is defined as at or below. So, if it is said at least, I have to choose lower number, but what is it? Is it 49.9; 49.99; 49.999; or... So that's why I think [tex]PR_{50}[/tex] is the best "hyprotika.wordpress.com"[/URL]
Problem c is just using z-score right? So I don't have to apply Normal Curve Equivalent here? Finding z-score for male rate, then using mean and standard deviaton for female rate, then that's the answer. Is it right?
Thanks for the answer. [PLAIN]"hyprotika.wordpress.com"[/URL]
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