AP Statistics Unit 3 Notes

Select components, when will a trial finish, determine response variable, run trials using RNG, summarize results, state your conclusion

select components

when will a trial finish

determine response variable

run trials using RNG

summarize results

state your conclusion

population

Sample

sample size

parameter proportion

statistic proportion

parameter mean

statistic mean

externally heterogenous, internally homogenous

internally heterogeneous, externally homogenous

control, randomized, replicable, blocking

control extraneous variables, not same as control group

best chance of equalizing effects of unknown sources of variance, does not eliminate unknown variables

Should be able to repeat with same sample or different sample, not have ridiculous amount of variability, one trial not enough

Split trial up based on another variable you think might play a role (like stratify) before assigning treatments, break up each block into treatment groups, block is experimental design vs strata is sample design

believe that x influences y, possible another variable influences y as well, can't tell which is causing y to happen combat by blinding, placebo, randomization

lurking (correlation) is hidden 3rd variable related to x and y, makes it look like x and y are related but they aren't, confounding (experiment) is causation found between x and y is muddle by other variable influencing y