Statz

math concerning the collection, organization, and the interpreation of data

statistics

the oberservations gathered from an experiment, survey, or study

data

data involving one random variable (ex) test scores

univariate

data involving two random variables (ex) test scores and hrs of studying

bivaraite

Describes the values in a data set, looking for patterns, (clusters, gaps, peaks), center maximum, minimum, range, spread outliers

distribution

number of values in a data set are represented by

n

what measure of center is least affected by outliers

median

how to find median

n+1/2

what symbol means sum

Σ

what means sample mean

X̄

what means population mean

μ

how to find range

max-min

interquartial range, range of the middle half of the data, not affected by outliers

IQR

average of the squared distances

variance

what means sample variance

s2

what means population varaiance

σ2

measure of variation that descries how far the data values are from the mean

standard deviation

Arranges the data by dividing it into 2 parts: stem and leaf. The legend tells you how to read it

Steam and leaf plot

Number line to show the number of times each value in a data set occurs, easily shows the shape of distribution

Dot plot

What spread does this have?

High spread / variance

Bar graph that displays the frequency of data divided into equal intervals (bins) the bars must be of equal width and should touch, not overlap

Histogram

Graph used to determine if a relationship / correlation exists between 2 sets of data

Scatter plot

Is this positive or negative and linear or nonlinear

Positive linear

What correlation does this scatter plot have?

No correlation

What is each part of a box and whisker plot worth in percentage?

25%

How to find outlier in less than

Q1-1.5IQR

How to find outlier in greater than

Q3+1.5IQR

entire set of items from which data is drawn

population

numerical value that states something about an entire population

parameter

collects info/data on every number of a population

census

a subset or a part of a population

sample

numerical value that states something about a sample

statistic

a study in which researchers gather existing info by observing subjects, recording records, etc

observational study

a study in which researchers apply a treatment to group and observe the effects of the treatment

experiment

the imitation of a real world process that requires a model to be developed

simulation

an investigation of one of more characteristics of a population

survey

Members are chosen using a method that gives everyone an equally likely chance of being selected

Simple random sample

Members are chosen using a pattern such as selecting every other person. Nth

Systematic sample

The population is first divided into groups. Then members are randomly chosen from each group

Stratified sample

The population is first divided into groups. A sample of the groups is randomly chosen. All members of the chosen group are surveyed

Cluster sample

Members are chosen because they’re easily accessible

Convenience sample

Members volunteer to participate

Self selected sample

error introduced by the sampling method. may skew the data and the results may not be accurate or truly represent the population

Bias

in right skewed distributions are mean or median greater

mean

in left skewed distributions are mean or median greater

median