Stat C1000 First Exam

data

information in all forms

categorical data

also called qualitative data; data in the form of labels that tells us something about the people or objects in the data set; country someone lives in, occupation, type of pet, etc.

quantitative data

data in the form of numbers that measure or count something; usually have units and taking an average makes sense; height, weight, salary, etc.

population

the collection of people or objects to be studied

census

collecting data from everyone in the population

sample

collecting data from a small subgroup of the population

random

when everyone in the population has a chance to be included in the sample

simple random sample

simple data in which individuals are selected randomly; tends to minimize sampling bias, good data collection method; normally participants are chosen by a computer

convenience sample

sample data that’s collected in a way that’s easy or convenient; tends to have a significant amount of sampling bias, bad way to collect data

voluntary response sample

sample data that’s collected by putting a survey out into the world and allowing anyone to fill it out; role of selection is given over to participants; significant amount of bias, bad method

cluster sample

sample method collecting data from groups of people in a population instead of one at a time; groups should be chosen to randomly to avoid sampling bias

stratified sample

sample method used to compare two or more groups or populations; individuals from each group should be chosen randomly

systematic sample

sample data that’s collected using a system, like choosing every 20th person on a list; more sampling bias than simple random, less than convenience and voluntary response

bias

when data does not accurately represent the population

sampling bias

results from collecting data without using a census or random sample; method of collecting is flawed (voluntary response, convenience sample)

question bias

a type of bias that results when someone phrases the question or gives it extra information with the goal of tricking the person into answering a certain way

how do we minimize question bias?

phrase questions in a neutral way and don’t attempt to sway the person giving data

response bias

results when people giving data do not answer truthfully or accurately; we should instead collect data anonymously and assure results will only be used for scientific purposes

non-response bias

results when people refuse to participate or give data; to minimize, you should give an incentive like a gift card to encourage people to give data

deliberate bias

results when people collecting the data falsify the reports, delete data, or decide to not collect data from certain groups in the population; to minimize, use good ethics