Stats 1.1-1.3 Vocab

Statistics

science of collecting, organizing, summarizing, and analyzing information (data) to draw conclusions

Individuals

entities that is measured in a study

• can be objects, cars, countries, or days

• “basic” definition/description

population

ENTIRE group to be studied

census

data collected from every individual in a population

• gives a reasonable alternative to select a study of a portion of individuals in a population

sample

the subset of a population in which is ACTUALLY collecting data

Parameter

numerical summary of the POPulation

• these values are usually unknown (unless a census is taken)

• value associated with the population

• identified with “P~.?”

statistic

numerical summary of a SAMple

• estimates the value of population parameters

• value associated with the sample

• identified with “P^~.?”

descriptive statistics

method for summarizing the collected data

• used by graphs, tables, and numerical summaries (averages or percentages)

• allows an overview of data and helps to determine the type of statistical method

inferential statistics

methods that take a result from a sample, extend it to the population, and measure the reliability of the result

• always contains uncertainty

margin of error

+-3

whats the process of statistics?

1. identify the research objective

2. collect the data needed to answer the question

3. describe the data

4. perform inference

distribution

what value a variable takes and how often it takes those values

• dictates the method of analysis that can be used

nomial level

name, label, categorize

• does not allow for rankings

• qualitiative

ordinal level

allows values to be ranked or ordered

• qualitative

interval level

values can be meaningfully added or subtracted

• a value of zero DOES NOT mean the absence of quantity

• ex. temperature

• quantitative

ratio level

values can be meaningfully multiplied or divided

• the value of zero MEANS the absence of quantity

• quantitative

experiment

researchers ASSIGN individuals in a study certain experimental conditions and observes the outcomes

• actively engaged

observational

researchers observes and records behaviors WITHOUT imposing any conditions

• controlling

representative sample

exhibits characteristics of those possessed by the population of interest

• MORE likely to obtain a representative sample if you let CHANCE determine the sample

simple random sample

n subjects from a population of size N is one in which each possible sample of size n has the same chance of being selected

• mainly rely on random number generators to generate these samples

does observational studies allow researchers to claim causation

no, only association

what do designed experiments allow?

researchers to identify certain cause and effect relationships

lurking variables

explanatory variable that was not considered in the study, but affects the value of the response variable and is typically also related to explanatory variables that were considered in the study