Quantitative Research Techniques
Statistics Peregrine
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: -
answersa sample
Significance level - answersMeasures the reliability of a statistical inference
inferential statistics - answersProcess of using sample statistics (mathematics) to draw
conclusions about population parameters
mutually exclusive - answersEvents that cannot occur at the same time.
sampling error - answersthe difference between the results of random samples taken at
the same time
non-sampling error - answersoccurs 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 - answersshort survey, short/simple questions,
start with demographic questions, ues dichtomous (yes-no) and multiple choice
Direct observation - answersexample: counts backpacks on campus for a day
stratified random sample - answersa 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 - answersthe probability of the intersection of two events
Union of two events - answersThe union of events A and B is the event containing all
sample points that are in A or B or both
Marginal Probability - answersthe probability of a single event without consideration of
any other event
Conditional Probability - answersthe likelihood that a target behavior will occur in a
given circumstance
Bayes Law - answerscalculates posterior probability
exhaustive - answersincluding everything possible; very thorough or complete
Central Limit Theorem (CLT) - answersThe 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.
sampling distribution of the mean - answers1. the sampling distribution of the mean has
a different mean from the original population
2. the standard deviation of the sampling distribution of the mean is referred to as the
standard deviation
3. if the original population is not normally distributed, the sampling of the mean will be
normal
Suppose you are given 3 numbers that relate to the number of people in a sample. The
three numbers are 10, 20 and 30. If the standard deviation is 10, the standard error
equals - answers5.77
To find the standard deviation, find the mean of the data set ( 10, 20, 30) then calculate
in excel. Watch video Bozeman Science Standard Error
Find the sample standard deviation of 5, 10, 15 and 20. - answers6.45
standard deviation - answersa computed measure of how much scores vary around the
mean score
Type 1 error - answersRejecting null hypothesis when it is true
type 11 error - answersfalse negative
Statistics Peregrine
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: -
answersa sample
Significance level - answersMeasures the reliability of a statistical inference
inferential statistics - answersProcess of using sample statistics (mathematics) to draw
conclusions about population parameters
mutually exclusive - answersEvents that cannot occur at the same time.
sampling error - answersthe difference between the results of random samples taken at
the same time
non-sampling error - answersoccurs 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 - answersshort survey, short/simple questions,
start with demographic questions, ues dichtomous (yes-no) and multiple choice
Direct observation - answersexample: counts backpacks on campus for a day
stratified random sample - answersa 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 - answersthe probability of the intersection of two events
Union of two events - answersThe union of events A and B is the event containing all
sample points that are in A or B or both
Marginal Probability - answersthe probability of a single event without consideration of
any other event
Conditional Probability - answersthe likelihood that a target behavior will occur in a
given circumstance
Bayes Law - answerscalculates posterior probability
exhaustive - answersincluding everything possible; very thorough or complete
Central Limit Theorem (CLT) - answersThe 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.
sampling distribution of the mean - answers1. the sampling distribution of the mean has
a different mean from the original population
2. the standard deviation of the sampling distribution of the mean is referred to as the
standard deviation
3. if the original population is not normally distributed, the sampling of the mean will be
normal
Suppose you are given 3 numbers that relate to the number of people in a sample. The
three numbers are 10, 20 and 30. If the standard deviation is 10, the standard error
equals - answers5.77
To find the standard deviation, find the mean of the data set ( 10, 20, 30) then calculate
in excel. Watch video Bozeman Science Standard Error
Find the sample standard deviation of 5, 10, 15 and 20. - answers6.45
standard deviation - answersa computed measure of how much scores vary around the
mean score
Type 1 error - answersRejecting null hypothesis when it is true
type 11 error - answersfalse negative
