data science - statistics II - sampling

Question 1

sample

Answer 1

a subset from a larger set of data

Question 2

population

Answer 2

the larger data set or idea of a data set

Question 3

N and n

Answer 3

Variable for population (N) and sample (n)

Question 4

random sampling

Answer 4

drawing elements into a sample at random - each member of the population has an equal opportunity of being selected

Question 5

stratified sampling

Answer 5

dividing the population into strata and randomly sampling from each strata

Question 6

simple random sampling

Answer 6

sample that results from random sampling w/o stratifying the population - each member of the population has an equal opportunity of being selected

Question 7

sample bias

Answer 7

a sample that misrepresents the population

Question 8

when does bias occur

Answer 8

when measurements or observations are systematically in error bc they are not representative of the full population

Question 9

vast search effect

Answer 9

bias or non-reproducibility resulting from repeated data modeling, or modeling data with large numbers of predictor variables

Question 10

sample statistic

Answer 10

metric calculated for a sample of data drawn from a larger population