Quantitative Research Techniques +
Statistics – Peregrine EXAM 2025
QUESTIONS AND ANSWERS
A company developed a smartphone whose average lifetime is unknown. In order to estimate
the average, 200 smartphones are randomly selected from a large production line and tested;
their average is found to be 5 years. The 200 smartphones represent: - ANS a sample
Significance level - ANS Measures the reliability of a statistical inference
inferential statistics - ANS Process of using sample statistics (mathematics) to draw
conclusions about population parameters
mutually exclusive - ANS Events that cannot occur at the same time.
sampling error - ANS the difference between the results of random samples taken at the
same time
non-sampling error - ANS occurs when the sample data are incorrectly collected, recorded,
or analyzed. Three types of errors: data acquisition errors, non-response errors (or bias),
selection bias
Design of a good survey components - ANS short survey, short/simple questions, start with
1
demographic questions, ues dichtomous (yes-no) and multiple choice
Page
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, Direct observation - ANS example: counts backpacks on campus for a day
stratified random sample - ANS a sample from selected subgroups of the target population in
which everyone in those subgroups has an equal chance of being included in the research
example: The manager of a customer service division wants to know if the customers in the
past 12 months are satisfied with their purchase of CD's. There are four types of CD's.
Joint Probability - ANS the probability of the intersection of two events
Union of two events - ANS The union of events A and B is the event containing all sample
points that are in A or B or both
Marginal Probability - ANS the probability of a single event without consideration of any
other event
Conditional Probability - ANS the likelihood that a target behavior will occur in a given
circumstance
Bayes Law - ANS calculates posterior probability
exhaustive - ANS including everything possible; very thorough or complete
Central Limit Theorem (CLT) - ANS The name of the theorem stating that the sampling
distribution of a statistic (e.g. x ) is approximately normal whenever the sample is large and
random. Allows us to draw conclusions about the population based on strictly sample data.
2
Page
@COPYRIGHT BRAINBARTER 2025/2026
Statistics – Peregrine EXAM 2025
QUESTIONS AND ANSWERS
A company developed a smartphone whose average lifetime is unknown. In order to estimate
the average, 200 smartphones are randomly selected from a large production line and tested;
their average is found to be 5 years. The 200 smartphones represent: - ANS a sample
Significance level - ANS Measures the reliability of a statistical inference
inferential statistics - ANS Process of using sample statistics (mathematics) to draw
conclusions about population parameters
mutually exclusive - ANS Events that cannot occur at the same time.
sampling error - ANS the difference between the results of random samples taken at the
same time
non-sampling error - ANS occurs when the sample data are incorrectly collected, recorded,
or analyzed. Three types of errors: data acquisition errors, non-response errors (or bias),
selection bias
Design of a good survey components - ANS short survey, short/simple questions, start with
1
demographic questions, ues dichtomous (yes-no) and multiple choice
Page
@COPYRIGHT BRAINBARTER 2025/2026
, Direct observation - ANS example: counts backpacks on campus for a day
stratified random sample - ANS a sample from selected subgroups of the target population in
which everyone in those subgroups has an equal chance of being included in the research
example: The manager of a customer service division wants to know if the customers in the
past 12 months are satisfied with their purchase of CD's. There are four types of CD's.
Joint Probability - ANS the probability of the intersection of two events
Union of two events - ANS The union of events A and B is the event containing all sample
points that are in A or B or both
Marginal Probability - ANS the probability of a single event without consideration of any
other event
Conditional Probability - ANS the likelihood that a target behavior will occur in a given
circumstance
Bayes Law - ANS calculates posterior probability
exhaustive - ANS including everything possible; very thorough or complete
Central Limit Theorem (CLT) - ANS The name of the theorem stating that the sampling
distribution of a statistic (e.g. x ) is approximately normal whenever the sample is large and
random. Allows us to draw conclusions about the population based on strictly sample data.
2
Page
@COPYRIGHT BRAINBARTER 2025/2026
