The age distribution of the students in Jane's cohort is normal. Jane graduated from the college at the age of 22. she is quite a bit younger than her cohort with the mean age of graduating for her cohort being 25 with a standard deviation of 1.3. How much younger than the rest of the class is in standard deviation units? what percentage class is younger than her?
Given

Jane's age, 

Jane is 2.31 standard deviations younger than rest of the class.
We need to find P(X < 22) =P( z < -2.31)
Using Emperical law
P(z < -2.31) = 0.0104 =1.04%b
Note : From z table of
to z , area from
to -2.31 is 0.0104
Therefore, 1.04% of the class is younger than her .
The age distribution of the students in Jane's cohort is normal. Jane graduated from the college...
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