NYU

Please do not print out these slides, future class slides will be updated throughout the course.  Thanks much.

Homework 1, Problem 1

p(healthy) = 75%

p(winter) = 25%

p(healthy | not winter) = 100%

p(sick | winter)?

A) -25%

B) 0%

C) 50%

D) 100%

E) 150%

Homework 1, Problem2

Dates 5 new employees started:

#1: 2000

#2: 2001

#3: 2003

#4: 2002

#5: 2005

Compute the average year and subtract the median year

A) 2002

B) 4004.2

C) -0.2

D) 0.2

Homework 1, Problem 3

Travel distance to home for employees (in a 100 population employee organization)

Take a random sample of 5 of these employees:

#1: 1 hour

#2: 2 hour

#3: 3 hour

#4: 2.5 hour

#5: 2 hour

What is the expected standard deviation of travel times?

A) 0.37

B) 0.44

C) 0.74

D) 1.11

Homework 1, Problem 4

You perform a national salary survey of mechanical engineers by examining your local area and come up with an average of $200k.  The real average salary nationally is $150k.  What happened?

A) positive bias of $50k

B) no bias

C) negative bias since you completed a local survey instead of a national one

Homework 1, Problem 5

What is the probability density function of being hungry per hour, between 9:00 and 9:06? Given:

20% probability of being hungry between 8:30 and 9:00

20% probability of being hungry between 9:06 and 9:25

A) 20%

B) 30%

C) 60%

D) 100%

E) 600%

Homework 2, Problem 1

A summary of a Poisson distribution of number of applicants a month is shown.  Standard deviation is 1.3.  What is the average?

0/month = 15%

1/month = 35%

2/month = 25%

3/month = 15%

4/month = 5%

5/month = 5%

A) 1.1-1.15

B) 1.3-1.35

C) 1.70-1.75

D) 1.8-1.85

E) 2.9-3

Homework 2, Problem2

You sample 49 wages below (all in $/hr).  What is the 1 standard deviation confidence interval about the expected value?

10, 10, 10, 10, 10, 10, 10

11, 11, 11, 11, 11, 11, 11

12, 12, 12, 12, 12, 12, 12

13, 13, 13, 13, 13, 13, 13

14, 14, 14, 14, 14, 14, 14

15, 15, 15, 15, 15, 15, 15

16, 16, 16, 16, 16, 16, 16

A) 11, to 15

B) 12.7, to 13.3

C) 13

D) 12.4, to 13.7

E) 12.9, to 13.1

Homework 2, Problem 3

You take a employee satisfaction survey of 100 employees and see that 75% of them are satisfied.  What is the standard deviation around your estimate of 75%?

A) 4%

B) 2%

C) 18%

D) 0.2%

E) 14%

Homework 2, Problem 4

You have a null hypothesis that employee Johnny is underperforming.  After the test, you reject the null hypothesis.  What do we state about Johnny?

A) He is underperforming

B) He is not underperforming

C) He is of approximately equal performance as everyone else

D) He is not overperforming

E) He is overperforming

Homework 2, Problem 5

You are provided a regression formula to determine an employees salary.  What is the slope of the regression?

Salary = (Age/10 * $40,000) - $20,000

A) $4,000

B) $1/10

C) $40,000

D) The salary

E) $20,000