Midterm 2 Vocabulary Chapters 4 to 6

Response variable is the…

outcome being predicted

Dependent variable is another name for?

another name for response variable

Explanatory variable is used to?

variable used to predict the response variable

Independent variable is another name for?..

another name for explanatory variable

Scatterplot

graph showing relationship between two quantitative variables

Scatterplot point

one observation with paired data

Correlation coefficient

number that measures strength and direction of linear relationship

r

symbol for correlation coefficient

Positive correlation

variables increase together

Negative correlation

one variable increases while the other decreases

No correlation

no linear relationship between variables

Strong correlation

data points are close to a line

Weak correlation

data points are spread out from a line

Positive r value

indicates positive correlation

Negative r value

indicates negative correlation

r near positive one

strong positive linear relationship

r near negative one

strong negative linear relationship

r near zero

little or no linear relationship

Coefficient of determination

percent of variation explained by regression

r²

symbol for coefficient of determination

r² meaning

percent of y explained by x

Regression line

line used to predict values

Least squares regression line

line with the smallest prediction errors

Regression equation

equation used to make predictions

y = a + bx

general regression equation

Slope

predicted change in y for every one unit increase in x

Positive slope

y increases as x increases

Negative slope

y decreases as x increases

Intercept

predicted value of y when x equals zero

Correlation

association between two variables

Causation

one variable directly causes another variable

Correlation versus causation

correlation does not prove cause

Sample space

all possible outcomes of a random process

Event

one or more outcomes from a sample space

Probability

likelihood that an event occurs

Probability value

number between zero and one

Impossible event

probability equals zero

Certain event

probability equals one

Equally likely outcomes

outcomes with the same probability

Mutually exclusive events

events that cannot happen together

Unusual event

event with very small probability

Law of Large Numbers

more trials make results closer to expected probability

Empirical method

probability based on collected data

Theoretical probability

probability based on possible outcomes

Complement rule

probability of not occurring

Probability of complement

1 - probability of event

Random variable

numerical outcome of a random process

Discrete random variable

random variable with countable outcomes

Continuous random variable

random variable with measurable outcomes

Discrete data

data counted with whole numbers

Continuous data

data measured on a scale

Probability distribution

list of values and their probabilities

Probability model

description of possible values and probabilities

Probability histogram

graph showing a probability distribution

Valid probability distribution

probabilities add up to one

Invalid probability distribution

probabilities do not add up to one