In: Math
Name Length of Service (in years)
William O. Douglas 36
Stephen Johnson Field 34
John Paul Stevens 34
John Marshall 34
Hugo Black 34
John Marshall Harlan 33
William J. Brennan 33
Joseph Story 33
James Moore Wayne 32
John Roberts 13
Please provide the following information (1 pt. each):
a. M years of service
b. SD years of service
c. Probability of observing the term length of John Roberts
a)
The mean for year of service time is obtained using the formula,
Where, X is the length of service time for judges.
From the data values,
Name | Length of Service (in years) |
William O. Douglas | 36 |
Stephen Johnson Field | 34 |
John Paul Stevens | 34 |
John Marshall | 34 |
Hugo Black | 34 |
John Marshall Harlan | 33 |
William J. Brennan | 33 |
Joseph Story | 33 |
James Moore Wayne | 32 |
John Roberts | 13 |
Sum | 316 |
b)
The standard deviation for the year of service times is obtained using the formula,
Length of Service (in years), X | ||
36 | 4.4 | 19.36 |
34 | 2.4 | 5.76 |
34 | 2.4 | 5.76 |
34 | 2.4 | 5.76 |
34 | 2.4 | 5.76 |
33 | 1.4 | 1.96 |
33 | 1.4 | 1.96 |
33 | 1.4 | 1.96 |
32 | 0.4 | 0.16 |
13 | -18.6 | 345.96 |
Sum | 394.4 |
c)
Let the data values are normally distributed with parameters, mean M and standard deviation, SD.
The probability of obtaining the length of service of John Roberts is obtained by calculating the z score
The probability for z score is obtained in excel using the function =NORM.S.DIST(-2.8097,FALSE)