ISDS CH. 7
Finite Population Correction Factor
A correction factor that accounts for the added precision gained by sampling a larger percentage of the population. It is implemented when the sample constitutes at least 5% of the population
What are the disadvantages to Cluster Sampling?
Less precision
Population
consist of all items of interest in a statistical problem
Cluster Sampling
dividing the population into groups such as geographic areas and then selecting a sample of the groups for the analysis
Central Limit Theorem
states that the sum or mean of a large number of independent observations from the same underlying distribution has an approximate normal distribution
Statistical Quality Control
statistical technique used to develop and maintain a firm's ability to produce high-quality goods and services
Stratified Random Sampling
the population is divided into groups (strata) based on one or more classification criteria
Nonresponse Bias
this occurs when those responding to a survey or poll differ systematically from the nonrespondents
Acceptance Sampling
used at the completion of a production process or service; if a particular product does not conform to certain specifications, then it is either discarded or repaired
What are the Disadvantages to Acceptance Sampling?
1. Costly to discard or repair a product 2. the detection of all defective products is not guaranteed
What are the two advantages to Stratified Random Sampling?
1. guarantees that the population subdivisions of interest are represented in the sample 2. the estimates of parameters produced from stratified random sampling have greater precision than estimates obtained from simple random sampling
What are the advantages to Cluster Sampling?
1. less expensive 2. useful when clusters occur naturally in the population
Selection Bias
refers to a systematic underrepresentation of certain groups from consideration of a sample
Bias
refers to the tendency of a sample statistic to systematically overestimate or underestimate a population parameter
Detection Approach
inspection occurs during the production process in order to detect any nonconformance to specifications - the goal is to determine whether the production process should be continued or adjusted before producing a large number of defects
Simple Random Sample
is a sample of "n" observations that has the same probability of being selected from the population as any other sample of "n" observations
Sample
is a subset of the population
The central limit theorem states that, for any distribution, as n gets larger, the sampling distribution of the sample mean ____________.
is closer to normal distribution
Social Desirability Bias
occurs when voters provide incorrect answers to a survey or poll because they think that others will look unfavorable on their ultimate choice