Stats Exam 2

Front 1

alternative hypothesis

Back 1

the hypothesis that the researcher usually wants to prove or verify; a statement about the value of a parameter that is either "less than," "greater than," or "not equal to"

Front 2

association

Back 2

values of one variable tend to occur with certain values of another variable; detected with the conditional distributions differ from the marginal distribution and from each other

Front 3

bias

Back 3

a condition where the mean of the statistic values differs from the parameter that the statistic estimates.

Front 4

bivariate data

Back 4

data collected on two variables for each individual/unit in a study

Front 5

C

Back 5

the symbol for level of confidence

Front 6

Central limit theorem

Back 6

the name of the statement telling us that the sampling distribution of x bar is approximately normal whenever the sample is large and random.

Front 7

conditional distribution

Back 7

the distribution of the values in a single row (or single column) of a two-way table

Front 8

conditions required for the sampling distribution of x-bar to be normal

Back 8

original population is normal and the sample is random

Front 9

confidence interval

Back 9

an estimate of the value of a parameter in interval form with an associated level of confidence; in other words, a list of reasonable values for the parameter based on a value of the statistic

Front 10

control chart

Back 10

a statistical tool for monitoring the input or output of a process

Front 11

control limits

Back 11

used to detect out-of-control signals in a control chart. equation is m plus or minus 3sigma over square root n. Could be 2 sigma if the question asks for it.

Front 12

correlation coefficient

Back 12

a measure of the strength of the linear relationship between to quantitative variables (r)

Front 13

decreased

Back 13

what happens to the width of a confidence interval when the sample size is increased.

Front 14

disjoint events

Back 14

events that cannot occur simultaneously

Front 15

distribution of a variable

Back 15

a list of the possible values of a variable together with the frequency of each value. Probabilities can be given instead of frequencies (because this is before the data has been collected)

Front 16

event

Back 16

a single outcome or a combination of outcomes from a random phenomenon

Front 17

extrapolation

Back 17

predicting a y value using a value of x that is outside the range of x values used to obtain the regression equation. this prediction could be very far off.

Front 18

garbage

Back 18

results from a statistical analysis performed on non-random samples

Front 19

increased

Back 19

what happens to the width of a confidence interval when the level of confidence is increased.

Front 20

inference

Back 20

using results from a sample statistic value to draw conclusions about the population parameter

Front 21

influential observation

Back 21

an observation that substantially alters the values of slope and y-intercept in the regression equation when it is included in the computations.

Front 22

law of large numbers

Back 22

the fact that the average of observed values in a sample will get closer and closer to the true mean as the sample size increases.

Front 23

law of probability

Back 23

the basis for hypothesis testing and interval estimation

Front 24

least squares

Back 24

a method for finding the equation of a line that minimizes the sum of squared residuals

Front 25

level of confidence

Back 25

the percentage of the time that the confidence interval procedure will produce confidence intervals that contain the parameter being estimated; the probability that the confidence interval to be computed (before the sample is taken and data are gathered) will contain the value of the parameter)

Front 26

lurking variable

Back 26

a variable that is not measured but explains association between two variables that are measured

Front 27

marginal distribution

Back 27

the distribution of the values in the "total" row or the "total" column of a two-way table

Front 28

margin of error

Back 28

the max. amount that a statistic value will differ from the parameter value for the middle of the distribution of all possible statistics

Front 29

mean of the sampling distribution of x-bar

Back 29

the mean of all the sample means from all possible samples of size n from a population; is equal to the true mean

Front 30

no association

Back 30

a condition where values of one variable occur independent of values of another variable; detected when the conditionals of a two-way table equal the marginal distribution (and each other)