STAT 230
OL4 / US2 Sections
Final Exam
Spring 2015
The final exam will be posted at 12:01 am on May 8, and it is due at 11:59 pm on May 10, 2015. Eastern Time is our reference time.
This is an openbook exam. You may refer to your text and other course materials as you work on the exam, and you may use a calculator. You must complete the exam individually. Neither collaboration nor consultation with others is allowed.
Answer all 25 questions. Make sure your answers are as complete as possible. Show all of your work and reasoning. In particular, when there are calculations involved, you must show how you come up with your answers with critical work and/or necessary tables. Answers that come straight from programs or software packages will not be accepted. If you need to use software (for example, Excel) and /or online or handheld calculators to aid in your calculation, please cite the sources and explain how you get the results.
Record your answers and work on the separate answer sheet provided.
This exam has 250 total points.
You must include the Honor Pledge on the title page of your submitted final exam. Exams submitted without the Honor Pledge will not be accepted.
1. True or False. Justify for full credit. (25 pts)
(b) P(A AND A^{c} ) 1, where A^{c} is the complement of A.
Refer to the following frequency distribution for Questions 2, 3, 4, and 5. Show all work. Just the answer, without supporting work, will receive no credit.
A random sample of 25 customers was chosen in UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon. The frequency distribution below shows the distribution for checkout time (in minutes).
Checkout Time (in minutes) 
Frequency 
Relative Frequency 
















1.0  1.9 
4 




2.0  2.9 

0.4 



3.0  3.9 





4.0  4.9 
5 










Total 
25 









2. 
Complete the frequency table with frequency and relative frequency. 
(5 pts) 

3. 
What percentage of the checkout times was at least 3 minutes? 
(5 pts) 

4. 
In what class interval must the median lie? Explain your answer. 
(5 pts) 
Refer to the following information for Questions 6, 7, and 8. Show all work. Just the answer, without supporting work, will receive no credit.
A 6faced die is rolled two times. Let A be the event that the outcome of the first roll is an even number, and B be the event that the outcome of second roll is greater than 4.
6. How many outcomes are there in the sample space? (5 pts)
first roll is an even number? (10 pts)
STAT 230 Introductory Business Statistics Final Examination Spring 2015 OL4/US2 
Page 3 of 6 

8. 
Are A and B independent? Why or why not? 
(5 pts) 



Refer to the following situation for Questions 9, 10, and 11.
The fivenumber summary below shows the grade distribution of two STAT 200 quizzes.

Minimum 
Q1 
Median 
Q3 
Maximum 






Quiz 1 
12 
40 
60 
95 
100 
Quiz 2 
20 
35 
50 
90 
100 
For each question, give your answer as one of the following: (a) Quiz 1; (b) Quiz 2; (c) Both quizzes have the same value requested; (d) It is impossible to tell using only the given information. Then explain your answer in each case. (5 pts each)
Refer to the following information for Questions 12 and 13. Show all work. Just the answer, without supporting work, will receive no credit.
There are 1000 juniors in a college. Among the 1000 juniors, 200 students are in the STAT200 roster, and 100 students are in the PSYC300 roster. There are 80 students taking both courses.
15. Imagine you are in a game show. There are 6 prizes hidden on a game board with 10 spaces. One prize is worth $100, another is worth $20, and four are worth $5.You have to pay $20 to the host if your choice is not correct. Let the random variable x be the winning. Show all work. Just the answer, without supporting work, will receive no credit.
16. Mimi just started her tennis class three weeks ago. On average, she is able to return 30% of her opponent’s serves. Assume her opponent serves 10 times. Show all work. Just the answer, without supporting work, will receive no credit.

probability distribution. What is the number of trials (n), probability of successes (p) and 


probability of failures (q), respectively? 
(5 pts) 
(b) 
Find the probability that that she returns at least 1 of the 10 serves from her opponent. 
(10 pts) 
(c) 
How many serves can she expect to return? 
(5 pts) 
Refer to the following information for Questions 17, 18, and 19. Show all work. Just the answer, without supporting work, will receive no credit.
The heights of pecan trees are normally distributed with a mean of 10 feet and a standard deviation of 2 feet.
18. Find the 3^{rd} quartile of the pecan tree height distribution. (5 pts)
20. A random sample of 225 SAT scores has a sample mean of 1500. Assume that SAT scores have a population standard deviation of 300. Construct a 95% confidence interval estimate of the mean SAT scores. Show all work. Just the answer, without supporting work, will receive
no credit. 
(10 pts) 







21. 
Consider the hypothesis test given by 




H _{0} : p 
0.5 



H_{1} : p 
0.5 




ˆ 
0.53 . 


In a random sample of 225 subjects, the sample proportion is found to be p 

(c) Is there sufficient evidence to justify the rejection of H_{0} at the 0.01 level?Explain. (15 pts)

Reaction Time (seconds) 

Subject 
Before 
After 
1 
6 
7 
2 
8 
8 
3 
4 
6 
4 
7 
10 
5 
9 
10 



Assume we want to use a 0.10 significance level to test the claim.
23. A STAT 230 instructor is interested in whether there is any variation in the final exam grades between her two classes Data collected from the two classes are as follows:
Her null hypothesis and alternative hypothesis are:
(c) Is there sufficient evidence to justify the rejection of H_{0} at the 
0.01 level? 
Explain. 
(10 pts) 



Spring 2015 OL4/US2 
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24. 
A random sample of 4 professional athletes produced the following data where x is the 

number of endorsements the player has and y is the amount of money made (in millions of 

dollars). 






















x 
0 
1 

3 

5 




y 
1 
2 

3 

8 


equation, without supporting work, will receive no credit. (15 pts)
Color 
Brown 
Yellow 
Orange 
Green 
Tan 
Number 
42 
21 
12 
7 
18 