Stats - CH8

measurement

the process of assigning number or labels to objects, events or phenomena according to specific rules

instrument

used to make a measurement

data

resulting measurements

Bureau of Labor Statistics (BLS)

reports unemployment every month

being unemployed requires

person must first be in the labor force, and must be available for work and looking for work

employed

on strike, but expect to return

not in the labor force

not working and haven’t looked for work for two weeks

not counted as unemployed

people who are not working but are too discouraged to seek employment

unemployment rate

number of people unemployed/ number of people in labor force

variable

valid measure of a characteristic if it is relevant or appropriate as a representation of that property

predicted validity

refers to how well a test or measurement can predict future outcomes that it is supposed to be related to

rate

more valid measure than a simple count of occurrences (used when you want to standardize for fair comparison across different populations or time periods)

measured value

true value + bias + random error

bias

measurement process systematically overstates or understates the true value

reliable

very small random error

reliability

consistency of a measurement

how dependable or repeatable it is under teh same conditions