Download STAT_230_QUIZ_2.

1.
Which of the following are measures of central tendency? Select all that apply
a.
b.
c.
d.
e.
f.
2.
Which of the following are measures of variability? Select all that apply
a.
b.
c.
d.
e.
f.
3.
mean
median
mode
Variance
standard deviation
linear transformation
mean
median
mode
variance
standard deviation
linear transformation
Rachael and Peter are discussing how the mean value and variance affect the
distribution graph. As the following graph shows, there are two distributions: A and B
Peter said that the distribution A has fatter tail because its has bigger standard deviation
than the distribution B. Rachael's answer is different:she thinks the distribution A has a
smaller standard deviation than the distribution B.
Who do you think is right?
a.
b.
c.
4.
Peter
Rachael
None of them are right. Distribution A and Distribution B have the same standard
deviation
In a bell-shaped distribution, changing ___can make the distribution flatter (i.e. more
compressed); and changing ___ can shift the distribution to the left or to the right.
a.
b.
c.
d.
Variance, mean
Mean, variance
Range, standard deviation
Mode, range
e.
f.
Mean, range
Mode, variance
5.
A research study found that in one physics class, the correlation between pre-exam
and post-exam grades was 0.90. The variance of pre-exam grades was 9 and the variance
of post-exam grades was 16. Thus, the variance of the difference between pre-exam and
post-exam grades is: (show work)
6.
Image that a researcher examined how the people’s heights are associated with their
salaries. She found that the correlation between heights (measured in inches) and salary
range (measured in dollars) was .36. Had she measured the height in cm instead, what
would the correlation have been?
a.
b.
c.
d.
e.
0.36
0.036
3.6
0.72
0.18
7.
The variance of X is 64 and the variance of y is 36. X and Y are independent. Thus,
the sum of the variances between X and Y is: (show work)
8.
A research study found that for the new-coming medical students, the correlation
between the trail Medical College Admission Test (MCAT) grades and real MCAT
grades was 0.60. The variance of pre-exam grades was 81 and the variance of post-exam
grades was 100. Thus, the variance of the difference between pre-exam and post-exam
grades is: (show work)
9.
One of the hallmarks of the scientific method is that it depends on empirical data.
a.
b.
10.
True
False
The best way to code a height measure of 1.8 meters would be to____
a.
b.
Have the subject write their height in inches
Have the subject record the information how they are comfortable, and then have the
researchers convert it over to inches if necessary
c. Leave it as is; the computer understands this notation
11.
If you wished to know how long since your subjects had eaten breakfast, it would be
better to ask them_____
a.
b.
What time they ate their breakfast and what time it is now
How many minutes since they ate breakfast
12.
The flaw in which a study samples too few observations from a segment of the
population is called___
a.
b.
c.
13.
Undercoverage bias
Survivorship bias
Self-selection bias
In a normal distribution, __ percentage of the area under the curve is within three
standard deviations of the mean?
a.
b.
c.
d.
68%
50%
95%
99%
14.
A normal distribution with a mean of 10 and standard deviation of 5. What is the
corresponding Z score for a case having a value of 7? (show work)
15.
For a normal distribution with a mean of 20 and standard deviation of 2, what is the
probability of getting a number greater than 26?
a.
b.
c.
d.
16.
5%
2.5%
1%
0.5%
A binomial distribution is a probability distribution for ____ events for which there
are ___ possible outcomes
a.
b.
c.
d.
Independent; two
Dependent; two
Independent; multiple
Dependent; Multiple
17.
In the figure above, what is an estimate the calories for a cereal with carbohydrate of 35
and fat of 5?
a.
b.
c.
d.
e.
f.
18.
between 75-100
between 100-125
between 125-150
between 150-175
between 175-200
greater than 200
The contour map shown above indicates that as fat and carbohydrates increase,
calories increase but not at a constant rate.
a.
b.
True
False
19.
The figure above shows...
a.
b.
20.
data that follows the assumed distribution.
data that does not follow the assumed distribution.
The q-q plot can be used to formally test the _________ hypothesis that the data are
normally distributed. This is done by computing the correlation coefficient of the n points
in the q-q plot.
a.
b.
null
alternative