STAT 1000 FINAL EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026
In terms of measuring the center, what does it mean when a data set is symmetrical? - Answers
Mean and median are the same
Describe the first quartile. - Answers Median of the observations left of the sample median
Describe the third quartile. - Answers Median of the observations located right of the sample median.
What are the components of the Five Number Summary? - Answers minimum, Q1, median, Q3,
maximum
What is the interquartile range? - Answers Q3 - Q1
When does standard deviation equal zero? - Answers When all observations have the same value
IQR and standard deviations are [blank]. - Answers measures of spread
What happens when you multiply observations by (b)? - Answers measures of center and spread get
multiplied by (b)
What happens when you add (a) to all observations? - Answers adds (a) to measures of center and
quartiles but not measures of spread stay the same
What happens of the mean and median when a density curve is skewed? - Answers mean gets pulled
in the direction of the skewness
Describe the 68-95-99.7 rule in terms of standard deviations. - Answers 68% = +/- 1 standard
deviations
95% = +/- 2 standard deviations
99.7% = +/- 3 standard deviations
What does a z-score tell us? - Answers how many standard deviations an observation falls above or
bellow the mean
Describe the coefficient of determination (r-squared). - Answers The percentage of the variation of y
explained by x
What is the equation for residuals? - Answers residual = observed - predicted
Explain common response in terms of observed association between two variables. - Answers Two
variables change in response to another variable
Explain confounding variables. - Answers When the effect of two variables on another variable
cannot be distinguished from one another
What is the difference between an observational study and an experiment? - Answers Observational
studies measures a variable(s) of interest while experiments measure the response of variable by
imposing a treatment
Describe a comparative experiment. - Answers When subjects are assigned to one of two or more
treatment groups (i.e. experimental vs. control)
When is a study biased? - Answers When results favor a particular direction
Describe matched pairs design. - Answers 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
Why is voluntary response sample a bad form of sampling? - Answers It's usually people at the
extremes who answer
How do stratified random samples work? - Answers Population divided into groups of similar
individuals called strata and an SRS is taken from each strata
Explain the importance of an institutional review board. - Answers It reviews all planned studies to
protect all subjects from harm
In terms of measuring the center, what does it mean when a data set is symmetrical? - Answers
Mean and median are the same
Describe the first quartile. - Answers Median of the observations left of the sample median
Describe the third quartile. - Answers Median of the observations located right of the sample median.
What are the components of the Five Number Summary? - Answers minimum, Q1, median, Q3,
maximum
What is the interquartile range? - Answers Q3 - Q1
When does standard deviation equal zero? - Answers When all observations have the same value
IQR and standard deviations are [blank]. - Answers measures of spread
What happens when you multiply observations by (b)? - Answers measures of center and spread get
multiplied by (b)
What happens when you add (a) to all observations? - Answers adds (a) to measures of center and
quartiles but not measures of spread stay the same
What happens of the mean and median when a density curve is skewed? - Answers mean gets pulled
in the direction of the skewness
Describe the 68-95-99.7 rule in terms of standard deviations. - Answers 68% = +/- 1 standard
deviations
95% = +/- 2 standard deviations
99.7% = +/- 3 standard deviations
What does a z-score tell us? - Answers how many standard deviations an observation falls above or
bellow the mean
Describe the coefficient of determination (r-squared). - Answers The percentage of the variation of y
explained by x
What is the equation for residuals? - Answers residual = observed - predicted
Explain common response in terms of observed association between two variables. - Answers Two
variables change in response to another variable
Explain confounding variables. - Answers When the effect of two variables on another variable
cannot be distinguished from one another
What is the difference between an observational study and an experiment? - Answers Observational
studies measures a variable(s) of interest while experiments measure the response of variable by
imposing a treatment
Describe a comparative experiment. - Answers When subjects are assigned to one of two or more
treatment groups (i.e. experimental vs. control)
When is a study biased? - Answers When results favor a particular direction
Describe matched pairs design. - Answers 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
Why is voluntary response sample a bad form of sampling? - Answers It's usually people at the
extremes who answer
How do stratified random samples work? - Answers Population divided into groups of similar
individuals called strata and an SRS is taken from each strata
Explain the importance of an institutional review board. - Answers It reviews all planned studies to
protect all subjects from harm
