SOLUTION: A study shows that scores on an aptitude test are normally distributed with a mean of 70 and a standard deviation of 12. Find the following probabilities: a. If one test taker is

Question 1161059: A study shows that scores on an aptitude test are normally distributed with a mean of 70 and a standard deviation of 12. Find the following probabilities:
a. If one test taker is selected, that the person scored greater than 75.
b. If 9 test takers are selected, that they have a mean score greater than 75. c. If 49 test takers are selected, that they have a mean score greater than 75.

Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
z=(x-mean)/sd
z > (5/12) with probability 0.3385
b. denominator is now sigma/sqrt (n), so z> (5/12/3) or z > 15/12 with probability 0.1056
c. z>35/12 with probability 0.0018
RELATED QUESTIONS
XYZ Corporation gives each of its employees an aptitude test. The scores on the test are... (answered by Boreal)

A math teacher gives two different tests to measure students� aptitude for math. Scores... (answered by ikleyn)

A math teacher gives two different tests to measure students� aptitude for math. Scores... (answered by Edwin McCravy)

Candidates for employment at a city fire department are required to take a written... (answered by ewatrrr)

A math teacher gives two different tests to measure students' aptitude for math. Scores... (answered by rothauserc)

Scores on an English test are normally distributed with a mean of 33.7 and a standard... (answered by Boreal)

You just have received your score in a language aptitude test. If your score was 82 and... (answered by solver91311)

it was found that 25% of all applicants for a position scored less than 160 points on an... (answered by stanbon)

An aptitude test is designed to measure leadership abilities of the test subjects.... (answered by stanbon)