Statistics 1 Flashcards
What is a population
Entire collection of units, items of individuals under investigation
What is a sample
Subset of population which we use to collect information
What does it mean to be “accurate” for a set of data?
Draw a correct conclusion so we have to aim for the “CORRECT” data
What does it mean to be “precise” for a set of data?
Have confidence in our conclusion so our variables are measure well and have small error
What can precision be split into?
Repeatability and Reproducability
What is repeatability
Can person producing the measurements repeat this in the future
What is reproducibility
Can second person reproduce the measurement made by the first person
What is a sampling error
Error in the estimate of some population characteristic e.g. total, mean, proportion
Occurs as it is a sample that is studied rather than the whole population
Sample estimate is not the same as a true population value
What are non sampling errors
Non sampling error cover all errors other than those due to sampling a subset of population
Give examples of non sampling errors and explain them
- Coverage error- inadequate sample to be able to represent entire population
- Non response error: failure to obtain information from sampling unit- person or variable
- Measurement errors- the recorded response differs from the true value
- Data handling errors- errors associated with the transcribing of data across mediums or storage
What does qualitative and quantitative mean?
Qualitative- represents characteristics
Quantitative- represents numerical in nature
What are the two different types of qualitative variables
Ordinal- variables have natural ordering (blood pressure is low, normal or high)
Nominal- where there is no natural ordering (Blood group O, A, B, AB)
What are the two different types of quantitative variables?
Discrete- take only a countable number of possible values
Continuous- unlimited number of possible values
- Person’s body mass index
- Person’s cholesterol measurement
