Answer:
a) The probability that a new college graduate in business will earn a starting salary of at least $65,000 is P=0.22965 or 23%.
b) The probability that a new college graduate in health sciences will earn a starting salary of at least $65,000 is P=0.11123 or 11%.
c) The probability that a new college graduate in health sciences will earn a starting salary of less than $40,000 is P=0.14686 or 15%.
d) A new college graduate in business have to earn at least $77,133 in order to have a starting salary higher than 99% of all starting salaries of new college graduates in the health sciences.
Step-by-step explanation:
<em>a. What is the probability that a new college graduate in business will earn a starting salary of at least $65,000?</em>
For college graduates in business, the salary distributes normally with mean salary of $53,901 and standard deviation of $15,000.
To calculate the probability of earning at least $65,000, we can calculate the z-value:
![z=\frac{x-\mu}{\sigma} =\frac{65000-53901}{15000} =0.74](https://tex.z-dn.net/?f=z%3D%5Cfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%20%3D%5Cfrac%7B65000-53901%7D%7B15000%7D%20%3D0.74)
The probability is then
![P(X>65,000)=P(z>0.74)=0.22965](https://tex.z-dn.net/?f=P%28X%3E65%2C000%29%3DP%28z%3E0.74%29%3D0.22965)
The probability that a new college graduate in business will earn a starting salary of at least $65,000 is P=0.22965 or 23%.
<em>b. What is the probability that a new college graduate in health sciences will earn a starting salary of at least $65,000?</em>
<em />
For college graduates in health sciences, the salary distributes normally with mean salary of $51,541 and standard deviation of $11,000.
To calculate the probability of earning at least $65,000, we can calculate the z-value:
![z=\frac{x-\mu}{\sigma} =\frac{65000-51541}{11000} =1.22](https://tex.z-dn.net/?f=z%3D%5Cfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%20%3D%5Cfrac%7B65000-51541%7D%7B11000%7D%20%3D1.22)
The probability is then
![P(X>65,000)=P(z>1.22)=0.11123](https://tex.z-dn.net/?f=P%28X%3E65%2C000%29%3DP%28z%3E1.22%29%3D0.11123)
The probability that a new college graduate in health sciences will earn a starting salary of at least $65,000 is P=0.11123 or 11%.
<em>c. What is the probability that a new college graduate in health sciences will earn a starting salary less than $40,000?</em>
To calculate the probability of earning less than $40,000, we can calculate the z-value:
![z=\frac{x-\mu}{\sigma} =\frac{40000-51541}{11000} =-1.05](https://tex.z-dn.net/?f=z%3D%5Cfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%20%3D%5Cfrac%7B40000-51541%7D%7B11000%7D%20%3D-1.05)
The probability is then
![P(X](https://tex.z-dn.net/?f=P%28X%3C40%2C000%29%3DP%28z%3C-1.05%29%3D0.14686)
The probability that a new college graduate in health sciences will earn a starting salary of less than $40,000 is P=0.14686 or 15%.
<em />
<em>d. How much would a new college graduate in business have to earn in order to have a starting salary higher than 99% of all starting salaries of new college graduates in the health sciences?</em>
The z-value for the 1% higher salaries (P>0.99) is z=2.3265.
The cut-off salary for this z-value can be calculated as:
![X=\mu+z*\sigma=51,541+2.3265*11,000=51,541+25,592=77,133](https://tex.z-dn.net/?f=X%3D%5Cmu%2Bz%2A%5Csigma%3D51%2C541%2B2.3265%2A11%2C000%3D51%2C541%2B25%2C592%3D77%2C133)
A new college graduate in business have to earn at least $77,133 in order to have a starting salary higher than 99% of all starting salaries of new college graduates in the health sciences.