INTRO TO STATISTICS FINAL EXAM
ACCURATE 100%
Population - ANSWER a collection of persons, things, or objects under study.
Sample - ANSWER selecting a portion (or subset) of the larger portion
Parameter - ANSWER A numerical characteristic of the whole population that can be
estimated by a statistic.
Ex: we consider all math classes to be the population, so the average number of points
earned per student over all math classes is a parameter.
Statistic - ANSWER A number that represents a property of the sample.
Ex: if we consider one math class to be the sample of the population of all the math
classes, then the average number of points earned by a student in that one math class
at the end of the term is an example of a statistic.
Variable - ANSWER usually letters x and y, is a characteristic or measurement that can
be determined for each number of the population
Numerical variable: takes on a value with equal units such as weights in pounds and
time in hours.
Categorical variable: place the person or thing into a category (ex: party affiliation,
gender, gpa).
Data - ANSWER the actual values of the variable
What are the levels of measurement? - ANSWER Nominal: no numerical value or order
(names, labels, categories)
Ordinal: usually no numerical value, but there is an order, however, the differences
between the data are meaningless (small, medium, large)
Interval: data can be ordered, and differences are meaningful
Ratio: can be ordered, differences are meaningful, and zero corresponds to none of the
values (0 is a measurement)
simple random sample - ANSWER each sample of the sample size has an equal
chance of being selected; simple random sample from the entire population
, Stratified Sampling - ANSWER Divide the entire population into distinct subgroups
called strata. The strata are based on a specific characteristic such as age, income,
education level, and so on. All members of a stratum share the specific characteristic.
Draw random samples from each stratum.
Cluster Sampling - ANSWER Divide the entire population into pre-existing segments or
clusters. The clusters are often geographic. Make a random selection of clusters.
Include every member of each selected cluster in the sample. Randomly select some
cluster.
Systematic Sampling - ANSWER randomly select a starting point and take every nth
piece of data from a listing of the population
Multistage Sampling - ANSWER Use a variety of sampling methods to create
successively smaller groups at each stage. The final sample consists of clusters.
Convenience Sampling - ANSWER Involves selecting participants who are readily
available without any attempt to make the sample representative of a population.
Midpoint - ANSWER A point that divides a segment into two congruent segments
lower boundary + upper boundary
__________________________________________________ = midpoint
2
Class Width - ANSWER the distance between lower (or upper) limits of consecutive
classes
largest data value - smallest data value
________________________________________________________ = class width
desired number of classes
z-score - ANSWER a measure of how many standard deviations you are away from the
norm (average or mean)
x-µ
z = ______________
σ
Central Limit Theorem - ANSWER If x is a random variable that is normally distributed,
then x̄ is normally distributed with the same mean and standard deviation of σ/srt n
µx̄ = µx σx̄ = σx/srt n
ACCURATE 100%
Population - ANSWER a collection of persons, things, or objects under study.
Sample - ANSWER selecting a portion (or subset) of the larger portion
Parameter - ANSWER A numerical characteristic of the whole population that can be
estimated by a statistic.
Ex: we consider all math classes to be the population, so the average number of points
earned per student over all math classes is a parameter.
Statistic - ANSWER A number that represents a property of the sample.
Ex: if we consider one math class to be the sample of the population of all the math
classes, then the average number of points earned by a student in that one math class
at the end of the term is an example of a statistic.
Variable - ANSWER usually letters x and y, is a characteristic or measurement that can
be determined for each number of the population
Numerical variable: takes on a value with equal units such as weights in pounds and
time in hours.
Categorical variable: place the person or thing into a category (ex: party affiliation,
gender, gpa).
Data - ANSWER the actual values of the variable
What are the levels of measurement? - ANSWER Nominal: no numerical value or order
(names, labels, categories)
Ordinal: usually no numerical value, but there is an order, however, the differences
between the data are meaningless (small, medium, large)
Interval: data can be ordered, and differences are meaningful
Ratio: can be ordered, differences are meaningful, and zero corresponds to none of the
values (0 is a measurement)
simple random sample - ANSWER each sample of the sample size has an equal
chance of being selected; simple random sample from the entire population
, Stratified Sampling - ANSWER Divide the entire population into distinct subgroups
called strata. The strata are based on a specific characteristic such as age, income,
education level, and so on. All members of a stratum share the specific characteristic.
Draw random samples from each stratum.
Cluster Sampling - ANSWER Divide the entire population into pre-existing segments or
clusters. The clusters are often geographic. Make a random selection of clusters.
Include every member of each selected cluster in the sample. Randomly select some
cluster.
Systematic Sampling - ANSWER randomly select a starting point and take every nth
piece of data from a listing of the population
Multistage Sampling - ANSWER Use a variety of sampling methods to create
successively smaller groups at each stage. The final sample consists of clusters.
Convenience Sampling - ANSWER Involves selecting participants who are readily
available without any attempt to make the sample representative of a population.
Midpoint - ANSWER A point that divides a segment into two congruent segments
lower boundary + upper boundary
__________________________________________________ = midpoint
2
Class Width - ANSWER the distance between lower (or upper) limits of consecutive
classes
largest data value - smallest data value
________________________________________________________ = class width
desired number of classes
z-score - ANSWER a measure of how many standard deviations you are away from the
norm (average or mean)
x-µ
z = ______________
σ
Central Limit Theorem - ANSWER If x is a random variable that is normally distributed,
then x̄ is normally distributed with the same mean and standard deviation of σ/srt n
µx̄ = µx σx̄ = σx/srt n
