Engineering Statistics Review For Exam printable pdf download

Engineering Statistics 1016-314

Review for Exam #2

Material for Exam #2:

• From the text: Chapter 3 (Section 6), Chapter 4 (Sections 1 – 4 and 6).

• Notes and Worksheets (#7 - #13) from Day 7 through Day 13, Homeworks 4 – 6, Mini-

Projects 3 – 5.

• Know how to use your calculators to enter data; calculate probabilities; obtain confidence

intervals, test statistics and p-values; and make a normal probability plot.

o These review problems cover the basic concepts for the exam, but should not be

considered to contain every possible piece of information you’ll need to know.

o The exam is closed book, closed notes. A 5x8 note card (both sides) and a calculator

are allowed. You’ll be expected to show your work to receive credit.

Problem #1

Researchers studying sleep claim that, among all adults, the average time to fall asleep in a dark

room is 16.5 minutes, with a standard deviation of 4.2 minutes. To investigate this claim,

Sleepy Sam will obtain a random sample of 50 adults and measure the time it takes for them to

fall asleep in a dark room.

A. Can Sleepy Sam be assured that his sample average will have a normal distribution?

EXPLAIN.

B. In a sample of 50 people (such as Sleepy Sam’s sample), a typical value for the average time

to fall asleep is ______. SHOW YOUR WORK.

C. The average time to fall asleep varies from sample to sample. In a sample of size 50, a

measure of variability for the average time to fall asleep is _______. SHOW YOUR WORK.

D. In samples of size 50, only 5% of the average times to fall asleep are less than ______.

SHOW YOUR WORK.

E. What is the probability that Sam’s sample average will be between 16 and 17 minutes?

SHOW YOUR WORK.

Problem #2

Polls are taken regularly to determine the public’s view on how the president is handling his job.

A January 2009 Gallup poll of 1015 U.S. adults over the age of eighteen contained 782 persons

who approved of Barack Obama’s handling of his job.

A. Does the data provide sufficient evidence to conclude that more than 75% of all US adults

approve of Obama’s handling of his job as president? USE THE APPROPRIATE STEPS.

B. If your conclusion in part A was incorrect, what type of error have you made? EXPLAIN.

Engineering Statistics Review For Exam