Module 0

Question 1

What is a Census and why is not usually collected

Answer 1

A census is a SAMPLE that includes EVERYONE (the entire population)

-it is time consuming
-expensive
under-coverage (may not actually include everyone)

Question 2

what are “sample statistics”

Answer 2

summaries found from data in a sample

Question 3

what are the two types of “inferences” that you can make with sample statistics

(just name the two)

Answer 3

1. Population Inference
2. Casual Inference

Question 4

What is a Population Inference

Answer 4

where the results from a. sample can be generalized to an ENTIRE population

Question 5

What is a Casual Inference

Answer 5

making conclusions from the results of two different variables or treatment groups

Question 6

what is Random Sampling

Answer 6

randomly selecting individuals in samples from the population (non-random leads to raised results)

Question 7

What is Simple random sampling

Answer 7

randomly picking people, the population has the same chance of being selected

Question 8

What is Stratified random sampling

Answer 8

the sample is first divided into different similar groups called STRATA

then you take a simple random sample fro each stata

Question 9

what is Cluster random sample

Answer 9

splitting the population into similar groups (clusters) then selecting a few clusters at random as samples

Question 10

what is Systematic random sample

Answer 10

selecting people of a population at a regular interval

ex.every 10th person that walks by

Question 11

what is Selection Bias (undercoverage)

Answer 11

when a portion of the population has a smaller representation in the sample or isn’t even sampled at all. They usually differ from the rest of the population

ex. an opinion poll conducted by telephone will miss out the households without home phones

Question 12

What is Response Bias

Answer 12

anything in a survey design that influences the responses
ex. respondents may lie if they don’t want to admit anything

Question 13

Voluntary Response Bias

Answer 13

when individuals can choose to participate in the sample

Question 14

What is Nonresponse Bias

Answer 14

When a large portion of those sampled fail to respond

Question 15

What is Random Allocation and what inference can you make with this

Answer 15

where you choose individuals for treatment groups by applying a random mechanism
ex. flipping a coin

causal inference

Question 16

What is an Observational Study

Answer 16

when an investigator observes individuals and measures variables but does NO attempt to influence the responses

Question 17

what is a retrospective study?

Answer 17

where individuals are sampled and information is collected about their PAST

Question 18

what is a Prospective Study?

Answer 18

where individuals are followed over time and data is being collected

Question 19

what are randomized experiments

Answer 19

a study design that allows us to prove a CAUSE-AND-EFFECT relationship