STATS unit 3 Vocab

entire group of individuals

easy to reach (bias)

a subset of individuals in population from which we select data

SRS= ever individual has equal chance of being selected// label individuals, randomize , select

people choose (bias due to strong opinions) themselves

classified into groups of similar individuals

classified into groups that are located near each other (elected all individuals in the cluster)

choose random start , then use equal interval

some member cannot be chosen in a sample

individual chosen can't be contacted or refuses to participate

pattern of inaccurate results

group of similar individuals(sampled from all groups)

groups with different individuals

most influential to given sample surveyed

observes individuals and measures variables of interest but does not attempt to influence the responses.

deliberately imposes some treatment on individuals to measure their responses.

occurs when two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other

A specific condition applied to the individuals in an experiment

the smallest collection of individuals to which treatments are applied

When the units are human beings

to perform a comparative experiment in which some units receive one treatment and similar units receive another

Comparison, Random assignment, control, replication

Use a design that compares two or more treatments

Use chance to assign experimental units to treatments. Doing so helps create roughly equivalent groups of experimental units by balancing the effects of other variables among the treatment groups.

Keep other variables that might affect the response the same for all groups

Use enough experimental units in each group so that any differences in the effects of the treatments can be distinguished from chance differences between the groups

the treatments are assigned to all the experimental units completely by chance

receives an inactive treatment or an existing baseline treatmen

The response to a dummy treatment

neither the subjects nor those who interact with them and measure the response variable know which treatment a subject received

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 treatments

the random assignment of experimental units to treatments is carried out separately within each block (like stratification)

for comparing two treatments, randomized blocked experiment in which each block consists of a matching pair of similar experimental units.

Sometimes, a “pair” in a matched-pairs design consists of a single unit that receives both treatments. Since the order of the treatments can influence the response, chance is used to determine with treatment is applied first for each unit.

An observed effect so large that it would rarely occur by chance = does imply causation.

cant happen by chance

less than 5% (p value of <0.05)

each sample has different results but they are from the same population

how far off the targeted

bigger sample, because narrower curve and less variability

if randomly assigned to group? inference of cause and effect

if randomly selected from population? inference about population

• association strong

• consistent association

• larger values of explanation associated with stronger responses

• alleged cause preceded the effect in time

• alleged cause is plausible

mean +_ margin of error (range)