Week 6 Flashcards
what is sampling bias?
systematic over or under-representation of a population in a sample
What is a sample size?
should be an accurate representation of the population
How to calculate sample size?
power analysis should be conducted before the sample is collected
What is power analysis?
estimate of sample size needed for accurate representation and want 0.8 for the results
What is a Type I error?
Rejecting the null when it is accurate. Calculated by Alpha
What is Alpha?
probability of rejecting the null when it is accurate out of 100 times. Should be compared with power
What is a type II error?
accepting the hypothesis when the null is correct, calculated by power
what is Power?
calculating the probability of making a type II error out of 100 times. Should be compared with alpha
what is non-probability sampling?
elements are highlighted to be shown, no randomization
what is probability sampling?
randomization used to collect a sample
what is convenience sampling?
using whoever is available for the sample
what is quota sampling?
non-probability with specific criteria to select specific populations to represent in a sample
what is simple random sampling?
define pop, list all units and then randomly select from that sample set
What is stratified random sampling?
pop divided into strat and then randomized into control or not
what is multistage/cluster sampling?
successive randomization of people who meet the eligibility criteria
