STAT 217 Midterm 1 Questions with Correct Answers (Grade A+)
Question 1: glimpse()
Answer: preview data in a set
Question 2: numerical variables
Answer: quantitative; can "do" math
Question 3: categorical
Answer: qualitative; distinct categories; can't be used in mathematical operations
Question 4: continuous numerical
Answer: can take on an infinite # of values within a given range; ex: height, money, mass, temperature,
speed
Question 5: discrete numerical
Answer: countable numeric variables
Question 6: categorical ordinal
Answer: categories have a natural/logical ordering
Question 7: categorical nominal
Answer: no inherent ordering; ex: yes/no
Question 8: fct
Answer: factor variable, aka categorical variable
Question 9: int
Answer: quantitative variable that takes only integer or whole number values
Question 10: dbl
Answer: double precision; quantitative variable that is essentially continuous (decimal values)
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, Question 11: count()
Answer: used to count info on subgroups
Question 12: pipe operator
Answer: tells R to pass the object that comes before it into the first argument of the function that comes after
it
Question 13: discretizing
Answer: converting a numerical variable to a categorical variable based on certain criteria
Question 14: observational study
Answer: no interference; results established on an association between explanatory and response variables
Question 15: experimental study
Answer: yes interference; random assignment into groups; establishes causal connections between
explanatory and response variables
Question 16: random assignment
Answer: assigning participants to experimental and control conditions by chance; can control/balance
confounding variables
Question 17: random sampling, random assignment
Answer: causal and generalizable to population
Question 18: random sampling, no random assignment
Answer: not causal, generalizable to population
Question 19: no random sampling, yes random assignment
Answer: causal, not generalizable
Question 20: no random sampling or random assignment
Answer: neither causal nor generalizable
Question 21: simple random sample
Answer: everyone gets a randomly selected number; numbers are then randomly chosen
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Question 1: glimpse()
Answer: preview data in a set
Question 2: numerical variables
Answer: quantitative; can "do" math
Question 3: categorical
Answer: qualitative; distinct categories; can't be used in mathematical operations
Question 4: continuous numerical
Answer: can take on an infinite # of values within a given range; ex: height, money, mass, temperature,
speed
Question 5: discrete numerical
Answer: countable numeric variables
Question 6: categorical ordinal
Answer: categories have a natural/logical ordering
Question 7: categorical nominal
Answer: no inherent ordering; ex: yes/no
Question 8: fct
Answer: factor variable, aka categorical variable
Question 9: int
Answer: quantitative variable that takes only integer or whole number values
Question 10: dbl
Answer: double precision; quantitative variable that is essentially continuous (decimal values)
Page 1
, Question 11: count()
Answer: used to count info on subgroups
Question 12: pipe operator
Answer: tells R to pass the object that comes before it into the first argument of the function that comes after
it
Question 13: discretizing
Answer: converting a numerical variable to a categorical variable based on certain criteria
Question 14: observational study
Answer: no interference; results established on an association between explanatory and response variables
Question 15: experimental study
Answer: yes interference; random assignment into groups; establishes causal connections between
explanatory and response variables
Question 16: random assignment
Answer: assigning participants to experimental and control conditions by chance; can control/balance
confounding variables
Question 17: random sampling, random assignment
Answer: causal and generalizable to population
Question 18: random sampling, no random assignment
Answer: not causal, generalizable to population
Question 19: no random sampling, yes random assignment
Answer: causal, not generalizable
Question 20: no random sampling or random assignment
Answer: neither causal nor generalizable
Question 21: simple random sample
Answer: everyone gets a randomly selected number; numbers are then randomly chosen
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