7: Sampling and Sampling Distributions Flashcards
What is selection bias?
This is when certain portions of a population are systematically under-represented
What is non-response bias?
This is where there is under-representation of certain groups to self-reporting
What is a simple random sample?
It’s a random sample taken from a population, everyone has an equal chance of being selected.
What is stratified random sampling?
Where a population is divided up into groups (MECE), mutually exclusive and collectively exhausted.
This helps fair subdivision of interests, groups can include religions, areas or ethnic groups.
What is cluster sampling?
Where a population is divided up into MECE groups.
Naturally occurring groups like suburbs or schools.
What is an estimator?
A variable produced from your sample such as sample mean.
It is an estimator of the population mean.
What makes an estimator unbiased?
When an expected variable equals the corresponding population parameter.
What is the standard error of the mean?
This is how we refer to the standard deviation of the mean of a population and is found by the standard deviation of the sample divided by sqrt(n).
The mean that we have found in our sample may not reflect the actual mean so we assign a degree of variability to it.
What is the acceptance approach in sampling?
When a business provides products, they inspect a portion of the products, if faulty, they will fix those.
What is the detection approach in sampling?
This observes the production process and identifies points where the process may not being meeting specifications.
What is chance variation?
This is uncontrollable chance of something happening
What is assignable variation?
This is a type of variation in a process and can usually be identified through events or factors and can be eliminated.
What is a control chart?
Where you monitor the factors of production against an upper and lower control limit to determine if something is operating as expected.
Central tendency can be observed in quantitative data as well as variability, failure rate in qualitative data.
