STAT 200: Introduction to Statistics
Final Examination, Spring 2016 OL1/US1
Page 1 of 7
STAT 200
OL1/US1 Sections
Final Exam
Spring 2016
The final exam will be posted at 12:01 am on March 4, and it is
due at 11:59 pm on March 6, 2016.
Eastern Time is our reference
time.
This is an open-book 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.
It is a violation of the UMUC Academic Dishonesty and Plagiarism policy to use
unauthorized materials or work from others.
Answer all 20 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 calculators, programs
or software packages will not be accepted.
If you need to use software (for
example, Excel) and /or online or hand-held calculators to aid in your calculation,
you must cite the sources and explain how you get the results.
Record your answers and work on the separate answer sheet provided
.
This exam has 200 total points; 10 points for each question.
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.

STAT 200: Introduction to Statistics
Final Examination, Spring 2016 OL1/US1
Page 2 of 7
1.
True or False.
Justify for full credit.
(a)
The standard deviation of a data set cannot be negative.
(b)
If P(A) = 0.4 , P(B) = 0.5, and A and B are disjoint, then P(A AND B) = 0.2.
(c)
The mean is always equal to the median for a normal distribution.
(d)
A 95% confidence interval is wider than a 98% confidence interval of the same parameter.
(e)
In a two-tailed test, the value of the test statistic is 1.5. If we know the test statistic follows
a Student’s t-distribution with P(T < 1.5) = 0.98, then we fail to reject the null hypothesis
at 0.05 level of significance .
2.
Identify which of these types of sampling is used: cluster, convenience, simple random,
systematic, or stratified.
Justify for full credit.
(a)
A STAT 200 professor wants to estimate the study hours of his students. He teaches two
sections, and plans on randomly selecting 10 students from the first section and 15 students
from the second section.
(b)
A STAT 200 student is interested in the number of credit cards owned by college students. She
surveyed all of her classmates to collect sample data.
(c)
The quality control department of a semiconductor manufacturing company tests every 100
th
product from the assembly line.
(d)
On the day of the last presidential election, UMUC News Club organized an exit poll in which
specific polling stations were randomly selected and all voters were surveyed as they left those
polling stations.
3.
The frequency distribution below shows the distribution for checkout time (in minutes) in
UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon.
(
Show all work. Just the
answer, without supporting work, will receive no credit.)
Checkout Time (in minutes) Frequency
Relative Frequency
1.0 - 1.9
3
2.0 - 2.9
12
3.0 - 3.9
0.20
4.0 - 4.9
3
5.0 -5.9
Total
25
(a)
Complete the frequency table with frequency and relative frequency. Express the relative
frequency to two decimal places.
(b)
What percentage of the checkout times was at least 4 minutes?
(c)
Does this distribution have positive skew or negative skew? Why?