STA 115 In-Class Notes Practice

Statistics is a set of [blank_start]procedures[blank_end] for analyzing info to help make a decision.

Science of data: used for collecting, organizing, displaying, describing, and [blank_start]analyzing[blank_end] data. Data: pieces of [blank_start]information[blank_end] collected.

Population: entire group Sample: [blank_start]subset[blank_end] of the population

Various ways of data collection: - surveys - observational studies (is there a [blank_start]relationship[blank_end]?) - experiments (is there [blank_start]cause[blank_end] and effect?)

Surveys Census: entire [blank_start]population[blank_end] is asked to respond to questions Sample Survey: [blank_start]sample[blank_end] is selected and asked

Observational Study vs. Experiment Observational Study: "What is" - look don't touch, no [blank_start]influence[blank_end] Problems with this? - can't determine [blank_start]cause[blank_end] & effect - if you want a cause & effect you would have to actively manipulate a variable ([blank_start]Experiment[blank_end]) Experiment: determines cause & effect

Inferential Statistics: analyses for data from a sample to infer something about a [blank_start]population[blank_end] Probability: likelihood that a certain outcome will [blank_start]occur[blank_end] Using statistics in the Research process: 1. Identify [blank_start]objective[blank_end] 2. Collect [blank_start]data[blank_end] 3. Organize, display, and [blank_start]describe[blank_end] data 4. [blank_start]Analyze[blank_end] data

It is important to avoid biased data.

Convenience sampling: selecting individuals who are [blank_start]easiest[blank_end] to reach Voluntary sampling: Individuals [blank_start]choose[blank_end] to be in the sample

You should always do convenience sampling or voluntary response sampling. You avoid bias by either selecting yourself or having people volunteer.