Stat unit 1 hw

Statistics

The science of collecting, organizing, summarizing, and analyzing information to draw conclusions or answer questions. In addition, providing a measure of confidence in any conclusions

Anecdotal

the information being conveyed is based on casual observation, not scientific research

population

entire group being studied

individual

a person or object that is a member of the group being studied

sample

a subset of the population that is being studied

a statistic

a numerical summary of the sample

descriptive statistics

organizing and summarizing data through numerical summaries like tables.

inferential statistics

extending results of the sample to the population and measuring the reliability of the result

parameter

a numerical summary of a population

4 steps of the process of statistics

1. identify research objective

2. collect data needed to answer objective

3. describe data

4. perform inference

variables

the characteristics of the individuals within the population

qualitative or categorical variables

allow for classification of individuals based on some attribute or characteristic

quantitative variables

provide numerical measures of individuals.

approach

a way to look at and organize a problem so that it can be solved

discrete variable

a quantitative variable that has either a finite number of possible values or a countable number of possible values.

continuous variable

a quantitative variable that has an infinite number of possible values that are not countable. needs to be measured

data frame

a data structure that organizes data into a table in which each row represents an individual and columns represent variables measured on each individual

nominal level of measurement

the values of the variable name, label, or categorize. In addition, the naming scheme does not allow for the values of the variable to be arranged in a ranked or specific order

ordinal level of measurement

it has the properties of the nominal level of measurement; however, the naming scheme allows for the values of the variable to be arranged in a ranked or specific order

interval level of measurement

has the properties of the ordinal level of measurement and the differences in the values of the variable have meaning. A value of zero does not mean the absence of the quantity. arithmetic operations like adding and subtracting can be performed

ratio level of measurement

has the properties of interval and the ratios of the values of the variable having meaning. a value of zero means the absence of the quanitity. arithmetic operations like multiplication and division can be performed on the values of the variable

determine level of measurement of: Race, temperature, number of day during the week that a student studied, letter grade earned in stats class

nominal, interval, ratio, ordinal

random sampling

process of using chance to select individuals from a population to be included in a sample

convenience sample

lazy way to sample and not effective

stratified sampling

obtained by separating population into nonoverlapping groups called strata, then obtaining a simple random sample from each stratum. individuals should be similar in some way.

systematic sampling

selecting every kth individual

cluster sampling

selecting individuals within randomly selected collection of individuals