Stats

difference of
observed y - predicted y
= y - ŷ

scatter plot of the regression residual against the explanatory variable.

a point that lies outside the overall pattern of the scatter plot.

if removing it would make a markedly change to the results of calculations

outliers in the x direction are usually influential to the least squares regression line

a variable that is not the explanatory or the response variable but it may influence the interpretation of the relationships among those variables

an association or comparison that holds for all several groups can reverse directions when the data are combined to form a single group.

x causes y

z causes x and y

z, and x are influential to y but do not cause y

comes from haphazardly selected individual cases, are striking in some way. these cases need not be representative of any larger group of cases
shows bias

data produced in the past that may help answer a present question

observe individual and measure variables of interest but do not attempt to influence the response

deliberately impose some treatment on individuals and observe their response

assigning people to groups randomly

two or more treatments to control the effect of lurking variables

use impersonal chance to assign experimental units to treatments

repeat to reduce chance of variation in the results

group of experimental units that are known before the experiment to be similar in some way that is expected to affect the response to the treatment.

the random assignment of units to treatments for each block

subject --> men--> random assignment--> group 1,2,3--> treatment 1,2,3--> compare survival

the random assignment of units to treatments for each block

subject --> women--> random assignment--> group 1,2,3--> treatment 1,2,3--> compare survival

the entire group of individuals that we want information about

part of the population that we actually examine in order to gather information

people who choose to respond, are bias b/c people with strong opinions are more likely to respond

individuals from the population chosen in such a way that every set of individuals has an equal chance to be the sample actually selected

chosen by chance. know what samples are possible and what chance each possible sample has

first divide the population into groups of similar individuals called strata. then choose a separate SRS in each stratum and combine these to form a full sample

when a population is left out of the process of choosing the sample

individual cant be contacted or doesn't cooperate

number that describes population
a fixed number that we do not know

describes a sample is known when we take a sample, can change from each sample
used to estimate unknown parameters

of a statistic, is the distribution of values taken by the statistic in all possible samples of the same size and from the same population

use random sampling

use a larger sample

variability: the spread of the sampling design and the sample size

reviews the planned studies in advanced in order to protect the subjects from possible harm

don't want a patten

always use total
% of people out of total
group total divided by total.
is/of= %/100

always use total
% of people out of one variable
individual total divided by total

of education level for each pet ownership group

when you see for that is the part you are talking about.

given that we are talking about pet ownership __% have ____education

The plan of the experiment which specifies the treatment conditions (independent variables ), what is to be measured (dependent variables ) and methods of assigning subjects to groups.

mean= μ
standard deviation= σ
proportion= p

mean= xˉ
standard deviation= s
proportion=p^
p hat