D772 Statistics Exam Questions with Correct Answers Latest Update 2025-2026
population - Answers an entire group of individuals or objects that you want to study
sample - Answers a smaller, more manageable group selected from the population to represent
the larger group
parameter - Answers a numerical value describing an entire population's characteristics
statistic - Answers a numerical value that describes a characteristic of a sample
individuals - Answers persons or objects described by a set of data
variables - Answers characteristics or measurements that we are interested in studying
quantitative variables - Answers numerical measurements, such as age, height, weight, or
income
categorical variables - Answers categories or labels, such as hair color, occupation, or favorite
type of food
data - Answers actual values of the variables (raw information) that we collect and analyze to
gain insights into the phenomenon we are studying
random sampling - Answers process that allows researchers to choose a random set of
individuals from a population
simple random sample - Answers sample chosen from a population from which each possible
subset of the same size has an equal probability of being chosen
stratified sampling - Answers method of random sampling that involves dividing the population
into distinct subgroups called strata, based on specific characteristics such as age, gender, or
socioeconomic status
cluster sampling - Answers method of random sampling that involves dividing the population
into clusters, which are naturally occurring groups like schools, neighborhoods, or cities
systematic sampling - Answers method of random sampling that involves selecting every nth
individual from a list of the population, starting from a randomly chosen point
explanatory variable - Answers variable that a researcher manipulates or observes changes in to
explain or predict the results
response variable - Answers variable that represents the outcome the researcher is interested in
explaining or predicting
observational study - Answers when researchers observe and record data on variables as they
naturally occur, without any intervention or manipulation
, sample survey - Answers specific type of observational study where individuals self-report the
values of variables, often by providing their opinions or answering questions
experiment - Answers when researchers intentionally manipulate one or more variables (the
explanatory variables) to observe their effect on another variable (the response variable)
treatments - Answers different values of the explanatory variable
experimental unit - Answers a single object or individual being measured
randomization - Answers when objects or individuals are randomly assigned (by chance) to an
experimental group
replication - Answers when the experiment is repeated with a sufficiently large sample size, or
reproducing the entire study to confirm previous findings
control group - Answers group of participants in an experiment who do not receive the
experimental treatment
placebo - Answers inactive treatment that has no real effect on the response variable
placebo effect - Answers when patients improve solely because they believe they are receiving
treatment, regardless of whether they are actually receiving the treatment
blinding - Answers technique used to prevent participants and/or researchers from knowing
who is receiving the experimental treatment and who is receiving the placebo
single-blind - Answers when only the participants are unaware of their treatment group
assignment
double-blind - Answers when both the participants and the researchers interacting with them are
unaware of the treatment group assignments
randomized, controlled, double-blind experiment - Answers most reliable way to determine
whether the explanatory variable is actually causing changes in the response variable
representative sample - Answers also known as an unbiased sample, is a subset of the
population that accurately reflects the characteristics of the larger group
non-representative sample - Answers also known as a biased sample, fails to accurately reflect
the population
volunteer sample - Answers non-random sample in which individuals have selected themselves
to be included in a study or experiment
voluntary response bias - Answers bias that occurs when mostly those with strong opinions or
particular interest in a study or experiment choose to participate
population - Answers an entire group of individuals or objects that you want to study
sample - Answers a smaller, more manageable group selected from the population to represent
the larger group
parameter - Answers a numerical value describing an entire population's characteristics
statistic - Answers a numerical value that describes a characteristic of a sample
individuals - Answers persons or objects described by a set of data
variables - Answers characteristics or measurements that we are interested in studying
quantitative variables - Answers numerical measurements, such as age, height, weight, or
income
categorical variables - Answers categories or labels, such as hair color, occupation, or favorite
type of food
data - Answers actual values of the variables (raw information) that we collect and analyze to
gain insights into the phenomenon we are studying
random sampling - Answers process that allows researchers to choose a random set of
individuals from a population
simple random sample - Answers sample chosen from a population from which each possible
subset of the same size has an equal probability of being chosen
stratified sampling - Answers method of random sampling that involves dividing the population
into distinct subgroups called strata, based on specific characteristics such as age, gender, or
socioeconomic status
cluster sampling - Answers method of random sampling that involves dividing the population
into clusters, which are naturally occurring groups like schools, neighborhoods, or cities
systematic sampling - Answers method of random sampling that involves selecting every nth
individual from a list of the population, starting from a randomly chosen point
explanatory variable - Answers variable that a researcher manipulates or observes changes in to
explain or predict the results
response variable - Answers variable that represents the outcome the researcher is interested in
explaining or predicting
observational study - Answers when researchers observe and record data on variables as they
naturally occur, without any intervention or manipulation
, sample survey - Answers specific type of observational study where individuals self-report the
values of variables, often by providing their opinions or answering questions
experiment - Answers when researchers intentionally manipulate one or more variables (the
explanatory variables) to observe their effect on another variable (the response variable)
treatments - Answers different values of the explanatory variable
experimental unit - Answers a single object or individual being measured
randomization - Answers when objects or individuals are randomly assigned (by chance) to an
experimental group
replication - Answers when the experiment is repeated with a sufficiently large sample size, or
reproducing the entire study to confirm previous findings
control group - Answers group of participants in an experiment who do not receive the
experimental treatment
placebo - Answers inactive treatment that has no real effect on the response variable
placebo effect - Answers when patients improve solely because they believe they are receiving
treatment, regardless of whether they are actually receiving the treatment
blinding - Answers technique used to prevent participants and/or researchers from knowing
who is receiving the experimental treatment and who is receiving the placebo
single-blind - Answers when only the participants are unaware of their treatment group
assignment
double-blind - Answers when both the participants and the researchers interacting with them are
unaware of the treatment group assignments
randomized, controlled, double-blind experiment - Answers most reliable way to determine
whether the explanatory variable is actually causing changes in the response variable
representative sample - Answers also known as an unbiased sample, is a subset of the
population that accurately reflects the characteristics of the larger group
non-representative sample - Answers also known as a biased sample, fails to accurately reflect
the population
volunteer sample - Answers non-random sample in which individuals have selected themselves
to be included in a study or experiment
voluntary response bias - Answers bias that occurs when mostly those with strong opinions or
particular interest in a study or experiment choose to participate
