STAT 1000 EXAM QUESTIONS AND 100%
CORRECT ANSWERS!!
Question 1
What happens of the mean and median when a density curve is skewed?
Correct Answer
mean gets pulled in the direction of the skewness
Question 2
What happens when you add (a) to all observations?
Correct Answer
adds (a) to measures of center and quartiles but not measures of spread stay the
same
Question 3
What is the interquartile range?
Correct Answer
Q3 - Q1
Question 4
Explain confounding variables.
Correct Answer
When the effect of two variables on another variable cannot be distinguished from
one another
Question 5
What are the components of the Five Number Summary?
Correct Answer
minimum, Q1, median, Q3, maximum
Page 1 of 88
,Question 6
Describe the third quartile.
Correct Answer
Median of the observations located right of the sample median.
Question 7
What does a z-score tell us?
Correct Answer
how many standard deviations an observation falls above or bellow the mean
Question 8
What happens when you multiply observations by (b)?
Correct Answer
measures of center and spread get multiplied by (b)
Question 9
Describe the first quartile.
Correct Answer
Median of the observations left of the sample median
Question 10
How do stratified random samples work?
Correct Answer
Population divided into groups of similar individuals called strata and an SRS is
taken from each strata
Question 11
Why is voluntary response sample a bad form of sampling?
Correct Answer
It's usually people at the extremes who answer
Page 2 of 88
,Question 12
Describe the 68-95-99.7 rule in terms of standard deviations.
Correct Answer
68% = +/- 1 standard deviations
95% = +/- 2 standard deviations
99.7% = +/- 3 standard deviations
Question 13
Explain the importance of an institutional review board.
Correct Answer
It reviews all planned studies to protect all subjects from harm
Question 14
In terms of measuring the center, what does it mean when a data set is symmetrical?
Correct Answer
Mean and median are the same
Question 15
Describe matched pairs design.
Correct Answer
blocking experimental units into pairs based on a shared characteristic (i.e. gender)
and randomly assigning treatment to one of the two in the pair
Question 16
When is a study biased?
Correct Answer
When results favor a particular direction
Page 3 of 88
, Question 17
Describe the coefficient of determination (r-squared).
Correct Answer
The percentage of the variation of y explained by x
Question 18
Describe a comparative experiment.
Correct Answer
When subjects are assigned to one of two or more treatment groups (i.e.
experimental vs. control)
Question 19
What is the equation for residuals?
Correct Answer
residual = observed - predicted
Question 20
Explain common response in terms of observed association between two variables.
Correct Answer
Two variables change in response to another variable
Question 21
When does standard deviation equal zero?
Correct Answer
When all observations have the same value
Page 4 of 88
CORRECT ANSWERS!!
Question 1
What happens of the mean and median when a density curve is skewed?
Correct Answer
mean gets pulled in the direction of the skewness
Question 2
What happens when you add (a) to all observations?
Correct Answer
adds (a) to measures of center and quartiles but not measures of spread stay the
same
Question 3
What is the interquartile range?
Correct Answer
Q3 - Q1
Question 4
Explain confounding variables.
Correct Answer
When the effect of two variables on another variable cannot be distinguished from
one another
Question 5
What are the components of the Five Number Summary?
Correct Answer
minimum, Q1, median, Q3, maximum
Page 1 of 88
,Question 6
Describe the third quartile.
Correct Answer
Median of the observations located right of the sample median.
Question 7
What does a z-score tell us?
Correct Answer
how many standard deviations an observation falls above or bellow the mean
Question 8
What happens when you multiply observations by (b)?
Correct Answer
measures of center and spread get multiplied by (b)
Question 9
Describe the first quartile.
Correct Answer
Median of the observations left of the sample median
Question 10
How do stratified random samples work?
Correct Answer
Population divided into groups of similar individuals called strata and an SRS is
taken from each strata
Question 11
Why is voluntary response sample a bad form of sampling?
Correct Answer
It's usually people at the extremes who answer
Page 2 of 88
,Question 12
Describe the 68-95-99.7 rule in terms of standard deviations.
Correct Answer
68% = +/- 1 standard deviations
95% = +/- 2 standard deviations
99.7% = +/- 3 standard deviations
Question 13
Explain the importance of an institutional review board.
Correct Answer
It reviews all planned studies to protect all subjects from harm
Question 14
In terms of measuring the center, what does it mean when a data set is symmetrical?
Correct Answer
Mean and median are the same
Question 15
Describe matched pairs design.
Correct Answer
blocking experimental units into pairs based on a shared characteristic (i.e. gender)
and randomly assigning treatment to one of the two in the pair
Question 16
When is a study biased?
Correct Answer
When results favor a particular direction
Page 3 of 88
, Question 17
Describe the coefficient of determination (r-squared).
Correct Answer
The percentage of the variation of y explained by x
Question 18
Describe a comparative experiment.
Correct Answer
When subjects are assigned to one of two or more treatment groups (i.e.
experimental vs. control)
Question 19
What is the equation for residuals?
Correct Answer
residual = observed - predicted
Question 20
Explain common response in terms of observed association between two variables.
Correct Answer
Two variables change in response to another variable
Question 21
When does standard deviation equal zero?
Correct Answer
When all observations have the same value
Page 4 of 88
