Econ 2310
Business Statistics: Problem Set #1
Instructions: You may use Excel and/or a calculator tocomplete this assignment. Please show work or reference what Excelcommands you used to solve the problems.
- You are given the following two series on income andcredit scores.
Income | FICO |
39 | 625 |
27 | 600 |
57 | 710 |
31 | 595 |
34 | 610 |
50 | 840 |
38 | 726 |
62 | 710 |
43 | 635 |
49 | 560 |
- Find the covariance and the correlation coefficient.(B) Do credit scores increase, decrease, stay the same, withIncome? (C) Create a scatter plot with Income and credit score.What do you see?
- Suppose you flip a fair coin four time. (A) What is theprobability you will get all four heads? (B) All four tails? (C)Either all four heads or four tails? (D) Anything but four heads orfour tails?
- Crime and Punishment: In a study of pleas and prisonsentences, it is found that 45% of the subjects studied were sentto prison. Among those sent to prison, 40% chose to plead guilty.Among those not sent to prison, 55% chose to pleadguilty.
- If one of the study subjects is randomly selected, findthe probability of getting someone who was not sent toprison.
- If a study subject is randomly selected and it is thenfound that the subject entered a guilty plea, find the probabilitythat this person was not sent to prison.
- In the BS Lottery (which stands for “BusinessStatistics”, of course), players choose 5 numbers out of 30. Theywin if they choose the same 5 numbers as our machine, which selectsthe numbers randomly. (A) How many permutations are possible? (B)How many combinations are possible?
- Below is a table of X and its frequency. What is themean of X? What is the standard deviation of X? What is thevariance of X?
X | Frequency |
2 | 20% |
5 | 10% |
8 | 15% |
10 | 30% |
12 | 25% |
