In: Statistics and Probability
According to the National Association of Colleges and Employers, the 2015 mean starting salary for new college graduates in health sciences was $51,541. The mean 2015 starting salary for new college graduates in business was $53,901. † Assume that starting salaries are normally distributed and that the standard deviation for starting salaries for new college graduates in health sciences is $11,000. Assume that the standard deviation for starting salaries for new college graduates in business is $17,000.
(a)
What is the probability that a new college graduate in business will earn a starting salary of at least $65,000? (Round your answer to four decimal places.)
(b)
What is the probability that a new college graduate in health sciences will earn a starting salary of at least $65,000? (Round your answer to four decimal places.)
(c)
What is the probability that a new college graduate in health sciences will earn a starting salary less than $46,000? (Round your answer to four decimal places.)
(d)
How much would a new college graduate in business have to earn in dollars in order to have a starting salary higher than 99% of all starting salaries of new college graduates in the health sciences? (Round your answer to the nearest whole number.)
$
Population mean, for heath science µ = 51541
Population standard deviation, σ = 11000
Population mean for business, µ = 53901
Population standard deviation, σ = 17000
a) Probability that a new college graduate in business will earn a starting salary of at least $65000 =
= P(X > 65000)
= P( (X-µ)/σ > (65000-53901)/17000)
= P(z > 0.6529)
= 1 - P(z < 0.6529)
Using excel function:
= 1 - NORM.S.DIST(0.6529, 1)
= 0.2569
b) Probability that a new college graduate in health sciences will earn a starting salary of at least 65000 =
= P(X > 65000)
= P( (X-µ)/σ > (65000-51541)/11000)
= P(z > 1.2235)
= 1 - P(z < 1.2235)
Using excel function:
= 1 - NORM.S.DIST(1.2235, 1)
= 0.1106
c) Probability that a new college graduate in health sciences will earn a starting salary less than 46000 =
= P(X < 46000)
= P( (X-µ)/σ < (46000-51541)/11000 )
= P(z < -0.5037)
Using excel function:
= NORM.S.DIST(-0.5037, 1)
= 0.3072
d) P(z > x) = 0.99
= 1 - P(z < x) = 0.99
= P(z < x) = 0.01
Z score at p = 0.01 using excel = ABS(NORM.S.INV(0.01)) = 2.33
Value of X = µ + z*σ = 51541 + (2.33)*11000 = $ 77171