NJIT CIS475 Lesson 4: Sampling
Each question has
only one best answer. Circle clearly the letter of
the best answer. If you make a mistake, cross out the circle, and write the
letter in capitals next to the question. If a question has both a capital
letter and is circled, the letter will be considered to be the answer.
1.
The list from which you take a sample is
called a:
a.
Sampling frame
b.
Population
c.
Quota sample
d.
Representative sample
e.
Random sample
2.
For a systematic random sample of 100 from
872, how big should the sampling interval be so everyone has a chance of being
chosen?
a.
Every 4th person should be sampled.
b.
Every 8th person should be sampled.
c.
Every 6th person should be sampled.
d.
Every 9th person should be sampled.
e.
You can’t tell as it depends on where you
start.
3.
Kevin thinks that gender and place of
residence influence perception about computer use. He obtains a list of voters
in the state of Vermont and divides the list into subpopulations of men who
live in small towns, men who live in large towns, women who live in small
towns, and women who live in large towns. He then randomly selects 200 people
from each subpopulation. What kind of sampling procedure is Kevin using?
a.
Non random sampling
b.
Systematic random sampling
c.
Cluster sampling
d.
Stratified random sampling
e.
Disproportionate stratified random sampling.
4.
Stratified random sampling:
a.
maximizes the within-group variance and
minimizes the between-group variance.
b.
Minimizes the within-group variance and
maximizes the between-group variance.
c.
Minimizes the effects of groups on the sample.
d.
Produces unbiased samples for small
populations but not for large ones.
e.
Eliminates all sampling error.
5.
In a street-intercept survey:
a.
A random set of streets is chosen and
interviews are conducted on corners wherever these streets intercept.
b.
You simply grab people who pass by on the
street.
c.
Interviewing is done in malls.
d.
Locations are selected at random and a random
selection of people who pass by are interviewed.
e.
Interviewing is done on street corners.
6.
What defines a normal distribution?
a.
It has a mean of 0 and a standard deviation of
1.
b.
It has a mean of 1 and a standard deviation of
0.
c.
It is symmetrical.
d.
In this case, normal is a synonym for typical.
e.
A uniform probability distribution is normal.
7.
The standard deviation is:
a.
A measure of spread in a normal distribution.
b.
A measure of how much the scores in a
distribution vary from the mean.
c.
The sum of the deviations squared.
d.
The standard error divided by sample size.
e.
The area within 10% of the mean of a
distribution.
8.
The planning committee of Little Place, USA,
surveyed a random sample of 100 households in town. They found that the average
household earned $37,500/per year, with a standard deviation of $2,000. What is
the standard error?
a.
$20
b.
$100
c.
$200
d.
$400
e.
$1000
9.
The planning committee of Rich Place, USA,
surveyed a random sample of 100 households in town. They found the average
household earned $45,000/peryear with a standard error of $500. Approximately
what would a 95% confidence interval look like?
a.
$40,000 - $50,000
b.
$44,500 - $45,500
c.
$42,500 - $47,500
d.
$44,020 - $45,980
e.
None of the above.
10.
What do you have to do to reduce the sampling
error of a point estimate by half?
a.
Double the sample size.
b.
Quadruple the sample size.
c.
Take the square of the sample size.
d.
Take the square root of the sample size.
e.
None of the above.
11.
Tom asked a random sample of 100 respondents
if they approved of Windows XP. Exactly 50% of the sample approved. What is the
95% confidence interval for this finding?
(Hint: P = P ±
Ö`PQ/n
)
a.
50% ±
5%
b.
50% ±
2.5%
c.
50% ±
1.25%
d.
50% ±
10%
e.
None of the aboce.