MMW Data Management

MEAN

SUM OF ALL VALUES DIVIDED BY THE NUMBER OF VALUES

MEDIAN

POSITIONAL MIDDLE VALUE

MODE

VALUE THAT OCCUR THE MOST FREQUENTLY

unimodal

one mode

bimodal

two modes

trimodal

three modes

Mean

Most popular measure of central tendency

meanaffected by extreme values

mean

mean is unique

true

Mean, Median

Useful when comparing sets of data

median

extreme values do not affect as much

mode may not exist

true

May not be unique

Mode

Mode

Extreme values do not affect

when no values repeat in data set

mode is useless

when there is one mode

it is difficult to interpret

Correlation Analysis

Strength and direction of the linear relationship between variables.

Simple Linear Regression Analysis

Parameters in a linear equation to predict the values of one variable.

Linear Regression

Statistical model that shows the relationship between two variables.

Regression Analysis

Involves graphing a line over set of data points.

Least-Squares Regression Line

Line that minimizes the sum of the squares of the vertical deviations.

equation for linear regression

y=bx+a

y

predicted values of y

b

slope or rate of change of y for each unit increase in x

a

y-intercept or level of y when x is 0

three main purpose of regression analysis

describe, predict, control

Scatter Plot

Used to present correlation of two variables.

correlation 0

no linear association

correlation 0 to 0.25

weak positive

correlation 0.25 to 0.75

moderate positive

correlation 0.75 to 1

strong positive

correlation 1

perfect positive