QBA test 1 || with 100% Error-free Answers.
Data Set correct answers The data that are collected for a particular study
Elements correct answers People, objects, events, or other entities within the data set
Variable correct answers any characteristic of an element
Measurement correct answers Numerical description of an element
Quantitative correct answers variable has a numerical characteristic
Qualitative correct answers variable has a non numerical characteristic
oberservational study correct answers researcher simply observe characteristis and take
measurements. ex surveys
Experimental study correct answers researchers impose treatments and controls then observe the
characteristics and take measurements
responce varible correct answers variable of interest
factors correct answers other variables which may be related to the response variable
Simple Random Sample (SRS) correct answers is chosen in such a way that each possible
sample of a given size is equally likely to be the one obtained
SRS with replacement correct answers units in the population can be chosen more than once
SRS without replacement correct answers units in the population cannot be chosen more than
once
Advantages of SRS correct answers (A) Most naturally understood of all sampling schemes
(B) Most easily understood of all sampling schemes
(C) Provides theoretical basis for more complicated sampling schemes
(D) Most single population basic statistical inference methers are appropriate only for data from
a SRS
Disadvantages of SRS correct answers Does not provide sufficient coverage when information
about subpopulations is required
May be impractical when the members of population are widely scattered
Cluster sampling correct answers Particulary useful when members of populations are widely
scattered geographically
, 1. divide the pop into clusters
2. obtain a SRS of the clusters
3. use all the members of the clusters obtained in Step 2 as the sample
Cluster sampling advatages correct answers (A) useful when members of the population are
widely scattered
(B) Easily implemented
(C) Can save time and money
Cluster sampling Disadvanges correct answers (A) traditional inference methods cannot be used.
Modifications of traditional methods exist for data collected using cluster smpling.
(B) Clusters may not mirror entire pop (ideally they should)
(C) Members of the clusters may be more homogeneous than the population
Stratified sampling correct answers more reliable than cluster samplng
(1) divide the pop into strata (Subpopulations)
(2) From each stratum obtain SRS of size proportional to the size of the stratum
(3) Use all members obatined in Step 2 as the sample
Stratified Sample advantages correct answers (A)More reliable than cluster sampling
(B) takes into account variability due to subpopulation differences
(C) traditional methods for comparing multiple pop can be based on data from a stratified
random sample
Stratified Sample Disadvantages correct answers (A) when the numbers of individuals in pop
strata are small , then traditional methods should not be applied to data
(B) cannot be used if the population cannot be completely partitioned into non-overlapping strata
Interval variable correct answers a measure of 0 does not imply the absence of measurement. ex)
Temperature, dates from AD, percentages
Ratio Varible correct answers 0 implies the absence of measurement
ex) height (in), weight, time (min) distance
Discrete varible correct answers all possible vaules represented in some type of list. ie counts
continuous varible correct answers all possible vaules must be represented by an interval. ie rates
frequency distribution correct answers a listing of all classes and their frequencies
relative frequency correct answers the proportion of observations in a class
relative frequency distribution correct answers a listing of all classes and their relative
frequencies
Data Set correct answers The data that are collected for a particular study
Elements correct answers People, objects, events, or other entities within the data set
Variable correct answers any characteristic of an element
Measurement correct answers Numerical description of an element
Quantitative correct answers variable has a numerical characteristic
Qualitative correct answers variable has a non numerical characteristic
oberservational study correct answers researcher simply observe characteristis and take
measurements. ex surveys
Experimental study correct answers researchers impose treatments and controls then observe the
characteristics and take measurements
responce varible correct answers variable of interest
factors correct answers other variables which may be related to the response variable
Simple Random Sample (SRS) correct answers is chosen in such a way that each possible
sample of a given size is equally likely to be the one obtained
SRS with replacement correct answers units in the population can be chosen more than once
SRS without replacement correct answers units in the population cannot be chosen more than
once
Advantages of SRS correct answers (A) Most naturally understood of all sampling schemes
(B) Most easily understood of all sampling schemes
(C) Provides theoretical basis for more complicated sampling schemes
(D) Most single population basic statistical inference methers are appropriate only for data from
a SRS
Disadvantages of SRS correct answers Does not provide sufficient coverage when information
about subpopulations is required
May be impractical when the members of population are widely scattered
Cluster sampling correct answers Particulary useful when members of populations are widely
scattered geographically
, 1. divide the pop into clusters
2. obtain a SRS of the clusters
3. use all the members of the clusters obtained in Step 2 as the sample
Cluster sampling advatages correct answers (A) useful when members of the population are
widely scattered
(B) Easily implemented
(C) Can save time and money
Cluster sampling Disadvanges correct answers (A) traditional inference methods cannot be used.
Modifications of traditional methods exist for data collected using cluster smpling.
(B) Clusters may not mirror entire pop (ideally they should)
(C) Members of the clusters may be more homogeneous than the population
Stratified sampling correct answers more reliable than cluster samplng
(1) divide the pop into strata (Subpopulations)
(2) From each stratum obtain SRS of size proportional to the size of the stratum
(3) Use all members obatined in Step 2 as the sample
Stratified Sample advantages correct answers (A)More reliable than cluster sampling
(B) takes into account variability due to subpopulation differences
(C) traditional methods for comparing multiple pop can be based on data from a stratified
random sample
Stratified Sample Disadvantages correct answers (A) when the numbers of individuals in pop
strata are small , then traditional methods should not be applied to data
(B) cannot be used if the population cannot be completely partitioned into non-overlapping strata
Interval variable correct answers a measure of 0 does not imply the absence of measurement. ex)
Temperature, dates from AD, percentages
Ratio Varible correct answers 0 implies the absence of measurement
ex) height (in), weight, time (min) distance
Discrete varible correct answers all possible vaules represented in some type of list. ie counts
continuous varible correct answers all possible vaules must be represented by an interval. ie rates
frequency distribution correct answers a listing of all classes and their frequencies
relative frequency correct answers the proportion of observations in a class
relative frequency distribution correct answers a listing of all classes and their relative
frequencies
