Chapter 1 - Class 1 Flashcards
What are statistics?
when were collecting, analyzing, and drawing conclusions
What do statistics assign a degree of?
a degree of certainty
What does statistics quantify the level of?
uncertainty from range and probability
What are the two categories of statistics?
the two categories of statistics are descriptive and inferential stats
What are descriptive stats?
organizing and summarizing numbers using charts, numbers, graphs with already known data
What is inferential statistics?
making conclusions based on a population
What techniques do inferential stats use?
estimation (degree of uncertainty) and hypothesis testing
What does descriptive stats illustrate?
average and variation
What is a statistical population?
all individuals for which we have an interest concerning some property
What is a census?
using all people in a population and surveying/testing them in some way (ACCURATE)
What is a sample?
involves a portion of the population since true values of population characteristics are usually unknown
What is random sampling?
to avoid bias, the population should represent our hypothesis and has an equal chance of being selected and that selection of each individual has no effect on the chance of selecting another individual (rock paper scissors, we are effected by the outcome of our choice and influenced by it for the next move)
What is precision?
how close you are to your other numbers
What is accuracy?
how close you are to the true value
What does it mean for a sample to be biased during accuracy testing?
when the sample produces too high or too low of values to the correct value
What is a stratified random sample?
taking entire population and breaking into common subpopulations and randomly picking/sampling from each subpopulation
What is the method to random sampling?
1) assign a number to the population
2) decide how many units/sample will be collected (n)
3) use a method to generate random integers from 1 to n
4) sample the n amount of units chosen and apply a characteristic
Where are stratified random samples used often?
in medicine
What are the two types of poor sampling designs?
convenience samples and voluntary responses
What are convenience samples?
sample individuals that are easy to reach and omit those that are difficult
What are voluntary samples?
relies on the decisions of volunteers is also commonly biased as they might represent specific social groups (ex: giving money as an incentive but only poor people come)
What is an independent population?
the population has no correlation to another population
