ELEMENTARY STATISTICS | EXAM READY - VERIFIED QUESTIONS
AND ANSWERS - COMPREHENSIVE LATEST VERSION
Q1. What is the difference between a population and a sample?
ANSWER A population includes all members of a defined group; a sample
is a subset of the population used to make inferences about the
population.
Q2. Define a parameter.
ANSWER A numerical measure that describes a characteristic of a
population (e.g., population mean μ).
Q3. Define a statistic.
ANSWER A numerical measure that describes a characteristic of a sample
(e.g., sample mean x̄).
Q4. What is descriptive statistics?
ANSWER The branch of statistics that involves organizing, summarizing,
and displaying data.
Q5. What is inferential statistics?
ANSWER The branch of statistics that involves using sample data to draw
conclusions about a population.
Q6. What is a quantitative variable?
ANSWER A variable that takes numerical values for which arithmetic
makes sense (e.g., height, weight, age).
Q7. What is a qualitative (categorical) variable?
ANSWER A variable that places individuals into categories or groups (e.g.,
gender, color, yes/no).
,Q8. Distinguish between discrete and continuous data.
ANSWER Discrete data can take only specific, separate values (usually
counts). Continuous data can take any value within a range (usually
measurements).
Q9. What is the difference between nominal and ordinal levels of
measurement?
ANSWER Nominal: categories with no natural order. Ordinal: categories
with a natural order, but differences between values are not meaningful.
Q10. What are the interval and ratio levels of measurement?
ANSWER Interval: ordered data with meaningful differences but no true
zero. Ratio: ordered data with meaningful differences and a true zero
point.
Q11. What is a simple random sample?
ANSWER A sample in which every member of the population has an
equal chance of being selected, and every possible sample of a given size
has an equal chance of being chosen.
Q12. What is a stratified sample?
ANSWER The population is divided into subgroups (strata) based on a
characteristic, and random samples are taken from each stratum.
Q13. What is a cluster sample?
ANSWER The population is divided into clusters, some clusters are
randomly selected, and all members of chosen clusters are included.
Q14. What is systematic sampling?
ANSWER Selecting every k-th member from a list after a random start.
Q15. What is convenience sampling?
ANSWER Choosing individuals who are easiest to reach; it is prone to
bias.
Q16. What is sampling bias?
ANSWER Bias that occurs when the sample is not representative of the
population due to the method of selection.
Q17. What is response bias?
ANSWER Bias that occurs when participants respond inaccurately or
untruthfully.
, Q18. What is nonresponse bias?
ANSWER Bias that occurs when individuals selected for the sample do
not respond, and they differ systematically from those who do.
Q19. What is an observational study?
ANSWER A study in which researchers observe subjects and measure
variables without assigning treatments.
Q20. What is an experiment?
ANSWER A study in which researchers deliberately impose treatments on
subjects to observe responses.
Q21. What is a placebo?
ANSWER A treatment with no active effect, used as a control in
experiments.
Q22. What is the placebo effect?
ANSWER The phenomenon where subjects respond favorably to a
placebo because they believe they are receiving an active treatment.
Q23. What is blinding in an experiment?
ANSWER Keeping participants and/or researchers unaware of who
receives which treatment to reduce bias.
Q24. What is a double-blind experiment?
ANSWER An experiment in which neither the participants nor the
researchers know who is receiving the treatment or the placebo.
Q25. What is a confounding variable?
ANSWER An extraneous variable that affects both the independent and
dependent variables, making it hard to determine causation.
Q26. What is a frequency distribution?
ANSWER A table that shows the number of times each value or category
occurs in a dataset.
Q27. What is a relative frequency?
ANSWER The proportion or percentage of observations in a category:
frequency divided by total observations.
Q28. What is a cumulative frequency?
ANSWER The sum of frequencies for all values up to and including the
current value.
AND ANSWERS - COMPREHENSIVE LATEST VERSION
Q1. What is the difference between a population and a sample?
ANSWER A population includes all members of a defined group; a sample
is a subset of the population used to make inferences about the
population.
Q2. Define a parameter.
ANSWER A numerical measure that describes a characteristic of a
population (e.g., population mean μ).
Q3. Define a statistic.
ANSWER A numerical measure that describes a characteristic of a sample
(e.g., sample mean x̄).
Q4. What is descriptive statistics?
ANSWER The branch of statistics that involves organizing, summarizing,
and displaying data.
Q5. What is inferential statistics?
ANSWER The branch of statistics that involves using sample data to draw
conclusions about a population.
Q6. What is a quantitative variable?
ANSWER A variable that takes numerical values for which arithmetic
makes sense (e.g., height, weight, age).
Q7. What is a qualitative (categorical) variable?
ANSWER A variable that places individuals into categories or groups (e.g.,
gender, color, yes/no).
,Q8. Distinguish between discrete and continuous data.
ANSWER Discrete data can take only specific, separate values (usually
counts). Continuous data can take any value within a range (usually
measurements).
Q9. What is the difference between nominal and ordinal levels of
measurement?
ANSWER Nominal: categories with no natural order. Ordinal: categories
with a natural order, but differences between values are not meaningful.
Q10. What are the interval and ratio levels of measurement?
ANSWER Interval: ordered data with meaningful differences but no true
zero. Ratio: ordered data with meaningful differences and a true zero
point.
Q11. What is a simple random sample?
ANSWER A sample in which every member of the population has an
equal chance of being selected, and every possible sample of a given size
has an equal chance of being chosen.
Q12. What is a stratified sample?
ANSWER The population is divided into subgroups (strata) based on a
characteristic, and random samples are taken from each stratum.
Q13. What is a cluster sample?
ANSWER The population is divided into clusters, some clusters are
randomly selected, and all members of chosen clusters are included.
Q14. What is systematic sampling?
ANSWER Selecting every k-th member from a list after a random start.
Q15. What is convenience sampling?
ANSWER Choosing individuals who are easiest to reach; it is prone to
bias.
Q16. What is sampling bias?
ANSWER Bias that occurs when the sample is not representative of the
population due to the method of selection.
Q17. What is response bias?
ANSWER Bias that occurs when participants respond inaccurately or
untruthfully.
, Q18. What is nonresponse bias?
ANSWER Bias that occurs when individuals selected for the sample do
not respond, and they differ systematically from those who do.
Q19. What is an observational study?
ANSWER A study in which researchers observe subjects and measure
variables without assigning treatments.
Q20. What is an experiment?
ANSWER A study in which researchers deliberately impose treatments on
subjects to observe responses.
Q21. What is a placebo?
ANSWER A treatment with no active effect, used as a control in
experiments.
Q22. What is the placebo effect?
ANSWER The phenomenon where subjects respond favorably to a
placebo because they believe they are receiving an active treatment.
Q23. What is blinding in an experiment?
ANSWER Keeping participants and/or researchers unaware of who
receives which treatment to reduce bias.
Q24. What is a double-blind experiment?
ANSWER An experiment in which neither the participants nor the
researchers know who is receiving the treatment or the placebo.
Q25. What is a confounding variable?
ANSWER An extraneous variable that affects both the independent and
dependent variables, making it hard to determine causation.
Q26. What is a frequency distribution?
ANSWER A table that shows the number of times each value or category
occurs in a dataset.
Q27. What is a relative frequency?
ANSWER The proportion or percentage of observations in a category:
frequency divided by total observations.
Q28. What is a cumulative frequency?
ANSWER The sum of frequencies for all values up to and including the
current value.
