STAT 1000 EXAM 8 QUESTIONS AND 100%
CORRECT ANSWERS!!
What is a population/target population?
the entire group of items/individuals (units) that we want information about
What is a census?
A special case when every unit in the population is measured or surveyed
What is a sampling frame?
The best list of items or people forming a population from which a sample is taken
What is a sampled population?
the collection of all possible observation units that might have been chosein in a sample; the
population from which the sample was taken
What is a sample?
The smaller group, the part of the population we actually examine in order to gather information
What is a parameter?
a (numerical) summary of a variable for the entire population
-usually unknown
What is a statistic?
a (numerical) summary of a variable for a sample
- used to estimate the parameter
What is bias?
Bias is the tendency of an estimate to deviate in one direction from a true value.
What is selection bias?
Selection bias occurs when the sample is non representative of the larger population of interest.
(The best way to avoid selection bias is to utilize randomness.)
, What is SRS?
Simple Random Sampling
Every unit in the population has an equal chance of being selected.
How is SRS done?
1. Assign each unit of the population a number
2. Use a random number generator to select which units to use
What are the advantages and disadvantages of SRS?
Advantage: easy to implement
Disadvantage: may not give representative sample always
What is stratified sampling? How is it done?
Stratified sampling is done by:
1. Dividing the population into strata
2. Selecting a SRS from each group
What is an advantage of stratified sampling?
Allows researcher to control on all variables that may influence outcome.
What is cluster sampling?
A cluster sample is obtained by selecting all individuals within a randomly selected collection or
group of individuals.
How is cluster sampling different from stratified sampling?
Stratified groups have more similarities within a group and more differences between groups.
Cluster groups have more similarities between groups and more differences within a group.
What is systematic sampling?
Systematic sampling is obtained by selecting every kth individual from the population.
How is k calculated in systematic sampling?
CORRECT ANSWERS!!
What is a population/target population?
the entire group of items/individuals (units) that we want information about
What is a census?
A special case when every unit in the population is measured or surveyed
What is a sampling frame?
The best list of items or people forming a population from which a sample is taken
What is a sampled population?
the collection of all possible observation units that might have been chosein in a sample; the
population from which the sample was taken
What is a sample?
The smaller group, the part of the population we actually examine in order to gather information
What is a parameter?
a (numerical) summary of a variable for the entire population
-usually unknown
What is a statistic?
a (numerical) summary of a variable for a sample
- used to estimate the parameter
What is bias?
Bias is the tendency of an estimate to deviate in one direction from a true value.
What is selection bias?
Selection bias occurs when the sample is non representative of the larger population of interest.
(The best way to avoid selection bias is to utilize randomness.)
, What is SRS?
Simple Random Sampling
Every unit in the population has an equal chance of being selected.
How is SRS done?
1. Assign each unit of the population a number
2. Use a random number generator to select which units to use
What are the advantages and disadvantages of SRS?
Advantage: easy to implement
Disadvantage: may not give representative sample always
What is stratified sampling? How is it done?
Stratified sampling is done by:
1. Dividing the population into strata
2. Selecting a SRS from each group
What is an advantage of stratified sampling?
Allows researcher to control on all variables that may influence outcome.
What is cluster sampling?
A cluster sample is obtained by selecting all individuals within a randomly selected collection or
group of individuals.
How is cluster sampling different from stratified sampling?
Stratified groups have more similarities within a group and more differences between groups.
Cluster groups have more similarities between groups and more differences within a group.
What is systematic sampling?
Systematic sampling is obtained by selecting every kth individual from the population.
How is k calculated in systematic sampling?
