Lesson 10: Univariate
Analysis
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.
What
is the difference between descriptive and inferential analysis?
a.
Inferential
analysis is qualitative and descriptive analysis is qualitative.
b.
Descriptive
analysis makes statements about data collected. Inferential analysis makes
statements beyond the data collected.
c.
Inferential
analysis involves making statements about data you have collected. Descriptive
analysis involves describing the world beyond the data you have collected.
d.
Descriptive
analysis refers to texts. Inferential analysis is about statistics.
e.
None
of the above.
2.
Mike
is teaching a large popular computer class that enrolls freshmen, sophomores,
juniors, and seniors. Mike wants to know how well students’ ages, education
levels, and parents’ income predict students’ final grades. What kind of
analysis does Mike need to do?
a.
Univariate
b.
Bivariate
c.
Multivariate
d.
Nonvariate
e.
Qualitative
3.
Tommy
asked 100 respondents if they liked different email systems. For each system he
wrote down a 1 if respondents said that they liked it and 0 if they said they
didn’t like it. What kind of variable does this create?
a.
Nominal
b.
Ordinal
c.
Ratio
d.
Neutral
e.
Qualitative.
4.
Jane
conducted a national mail survey of 300 people. One of the pieces of data she
recorded was the zip code from which the survey was mailed. What kind of
variable is ZIPCODE?
a.
Nominal
b.
Ordinal
c.
Ratio
d.
Neutral
e.
Qualitative
5.
What
does it mean to collapse a variable?
a.
To
eliminate it from further analysis
b.
To
take an interval or interval variable and reduce the number of values.
c.
To
remove the outliers
d.
To
calculate the central tendency
e.
None
of the above.
6.
What
are measures of central tendency good for?
a.
To
measure the degree of heterogeneity of a variable.
b.
To
measure the degree of homogeneity of a variable.
c.
To
measure the range of a variable.
d.
To
measure the minimum and maximum value of a variable.
e.
To
measure the typical value of a variable.
7.
In
a study of younger New Hampshire users, the Keene
Daily News reports that more
users browse with Explorer than any other. What kind of statistic is the Keene Daily News reporting?
a.
Mean
b.
Mode
c.
Median
d.
Standard
deviation
e.
Variance.
8.
Tom
reports that 50% of test scores in his class were above 79 and 50% were below
this point. What kind of statistic is Tom reporting?
a.
Mean
b.
Mode
c.
Median
d.
Standard
deviation
e.
Variance
9.
Lisa
records the number of hits per hour for 8 bulletin boards as 1, 3, 5, 26, 54,
57, 59, 75. What is the median?
a.
26
b.
35
c.
40
d.
53
e.
none
of the above.
10.
The
median represents what percentile?
a.
The
first quaratile
b.
The
third quartile
c.
The
interquartile range
d.
The
50th percentile
e.
It
depends on the data.
11.
How
do you calculate the mean of a set of numbers
a.
Sum
the individual scores in a distribution and divide by the number of scores.
b.
Take
the smallest number and add the biggest number and divide by two.
c.
Subtract
the distribution average from each number and sum the differences.
d.
Subtract
the distribution average from each number and square the result. Sum these
squared differences and divide by the number of items in the set.
e.
None
of the above.
12.
In
a demographic survey of 20 households, Tom finds 4 households with 4 children, 4
households with 3 children, 4 households with 2 children, 4 households with 1
child, and 4 households with no children. What is the mean number of children
per household
a.
1.5
b.
2
c.
2.5
d.
3
e.
5
13.
Alex
ran a telephone survey during the late morning on a Tuesday. He interviewed
people with the following ages: 15, 55, 57, 58, 58, 60, 63, 70. Which age(s)
is(are) the outliers?
a.
15
b.
17
and 70
c.
58
d.
58
and 58
e.
None
of the above.
14.
In
a distribution that is skewed to the right, you should expect that:
a.
There
are two modal responses
b.
The
median equals the mean
c.
The
median is smaller than the mean
d.
The
median is bigger than the mean
e.
The
mode is bigger than the mean.
15.
On
examining the distribution of one of his interval-level variables, Robert
discovers that the distribution around the mean and median are quite
symmetrical. What should he use as an estimator of the central tendency?
a.
Mean
b.
Median
c.
Mode
d.
Range
e.
Standard
deviation.
16.
What
is the standard deviation?
a.
It
is a formal measure of skewedness.
b.
It
results from subtracting the mean from each observation, squaring and summing
the differences, and dividing by the sample size minus 1.
c.
It
is the average squared deviation from the mean.
d.
It
is a measure of how much, on average, the scores in a distribution deviate from
the mean.
e.
None
of the above.
17.
John
asks 100 people to report their average income. The mean income for the sample
is $37,500, and the variance is $2,500. What is the standard deviation for
John’s sample?
a.
$25
b.
$50
c.
$500
d.
$2,500
e.
You
cannot tell from the available information.
18.
Tim
wants to test whether the average age of his sample of 200 respondents is the
average age of the population from which his sample was drawn. What is Tim’s
null hypotheses?
a.
Any
difference between the sample mean and the population mean is produced by
chance.
b.
There
is a difference, not due to chance, between the sample mean and the population
mean.
c.
The
sample mean will vary less than the population mean.
d.
The
sample mean will vary more than the population mean.
e.
Both
a and c above.
19.
Jenny
set her experiment significance level at 0.01. This means that:
a.
It
if the sample is 1% bigger than the mean of the population, she cannot reject
her null hypothesis.
b.
If
the sample is 1% bigger than the mean from the population, she can reject her
null hypothesis.
c.
If
a mean or a proportion from a sample is likely to occur more than 1% of the
time, then she cannot reject her null hypothesis.
d.
If
a mean or a proportion from a sample is likely to occur more than 1% of the
time, then she can reject her null hypothesis.
e.
It
is just an arbitrary cutoff Jenny picked to report results.
20.
Rejecting
the null hypothesis by mistake is what kind of error?
a.
A
Type I error.
b.
A
Type II error.
c.
A
Type III error.
d.
A
sampling error.
e.
A
standard error.
21.
What
should an investigator do to avoid a Type I error?
a.
Set
the alpha level of significance at a bigger number (e.g. 0.1)
b.
Set
the alpha level of significance at a very small number (e.g. 0.001)
c.
Reduce
the sample size.
d.
Increase
the sample size.
e.
None
of the above.
22.
What
is a standard error?
a.
The
amount of error distributed around the mean sample.
b.
The
standard deviation divided by the square root of the sample size.
c.
The
amount of error in poor measurements.
d.
The
amount of error we make in estimating a population parameter from a sample
statistic.
e.
Both
b and d are correct.
23.
Homero
is studying online trading and income. Homero identifies a very small sample (N=10)
of traders with low incomes. He wants to know if this sample is significantly
different from the average since he knows the US average income. What statistic
should he use to test if there are differences?
a.
95%
confidence intervals.
b.
Student’s
t.
c.
Standard
deviations
d.
Univariate
chi-square
e.
None
of the above.
24.
What
does a Z-score tell you?
a.
The
sum of the standard deviations.
b.
The
same thing as a t-statistic, except for larger samples.
c.
The
degree to which a population is heterogeneous, using standardized units.
d.
How
much standard error there is in any distribution.
e.
How
far, in standard deviations, a real score is from the mean of the distribution.
25.
What
does a univariate chi-square test do?
a.
It
tests whether the means of two distributions are significantly different from
one another by chance along.
b.
It
tests whether the distribution of a series of counts is likely to occur by
chance.
c.
It
tests whether the mean of a sample is likely to include the mean of the
population from which the sample was taken.
d.
It
tests interval level associations.
e.
None
of the above.
26.
T
F It is impossible to calculate a median with interval-level data.
a.
True
b.
False
27.
T
F When data are normally distributed, the mean is the best indicator of central
tendency.
a.
True
b.
False
28.
T
F Whenever possible, investigators should avoid collecting grouped data when
they can collect interval-level data.
a.
True
b.
False
29.
In
samples with a normal distribution, the mean, median, and mode are the same.
a.
True
b.
False
30.
T
F Most real data is normally distributed.
a.
True
b.
False
31.
T
F If a population is homogeneous with regard to some variable, then the
standard deviation of the mean of that variable should be small.
a.
True
b.
False
32. T F Use a two-tailed test when you are interested only in whether the magnitude or some stat