how surveys are used in marketing, algebra homework help

Use the information on

page 761

to explain how surveys are used in marketing. Find the margin of error for those who spend $249 or less if 807 mothers were surveyed. Explain what this margin of error means.

12-10
Sampling and Error
Main Ideas
. Determine whether
spleisubined
. Find more
samping mer
New Vocabulary
unbiased sample
margin of sampling
GET READY for the Lesson
A survey was
Back-to-School Clothes Spending
conducted asking
mothers how much
$249 or less
they spend per student S250-5349
on back-to-school
$300 or more
clothing. The results of
10%
Don’t know
the survey are shown.
20%
When polling
49%
organizations want
to find how the public
215
feels about an issue,
they survey a small
portion of the
population
Bias To be sure that survey results are representative of the population,
polling organizations need to make sure that they poll a random or
unbiased sample of the population.
Study Tip
Random Sample
A sample of sienis
random when every
possible sample of me
has an equal chance
of being selected
EXAMPLE Biased and Unbiased Samples
State whether each method would produce a random sample.
Explain.
a. asking every tenth person coming out of a gym how many times a
week they exercise to determine how often city residents exercise
This would not result in a random sample because the people
surveyed probably exercise more often than the average person
b. surveying people going into an Italian restaurant to find out
people’s favorite type of food
This would probably not result in a random sample because the
people surveyed would probably be more likely than others to
prefer Italian food
Proneck Your Progress
1. asking every player at a golf course what sport they prefer to watch
on TV
Margin of Error The margin of sampling error (ME) gives a limit on the
difference between how a sample responds and how the total population
would respond
Extra Ecamples at algebra.com
Lesson 12-10 Sampling and Error 741