Chapter 1

Question 1

What is Sampling Bias?

Answer 1

Sample was not representative of the population

Question 2

What is Non-response bias?

Answer 2

A lack of response from a significant amount of the population.

Question 3

Simple Random Sample

Answer 3

-every member of the population has the same chance of being included in the sample (sample is representative of the population)
-members of the sample are chosen independently of each other

Question 4

Ascertainment (or sampling) bias

Answer 4

some members of the population are less likely to be included than others

Question 5

What are two examples of nonsimple random sampling?

Answer 5

Random Cluster Sampling and Stratified Random Sampling

Question 6

What is a random cluster sample?

Answer 6

-divide forest in to smaller geographical sectors
-take a simple random sample of sectors
-count all the butterflies in these sectors and scale appropriately

Question 7

What is a stratified random sample?

Answer 7

-divide population into groups based on age, income, etc
-collect simple random samples of each group and scale appropriately

Question 8

What are some of the challenges to random cluster sampling and stratified random sampling?

Answer 8

-outliers propagate too large and there are different ways to make groups

Question 9

What is anecdotal evidence?

Answer 9

-a small observation or story

Question 10

What is an observational study?

Answer 10

-the researcher collects more data but they only an observer, they do not manipulate conditions or do an experiment

Question 11

What is a confounding variable?

Answer 11

-an extra variable that was not accounted for

Question 12

Which treatment is better?

Answer 12

Treatment A is better for both small stones and large stones because it is important to look at the sample size. Even though doctors favor treatment B for small stones and treatment A for large stones.

Question 13

What is it called when the doctor’s choice of treatment affected results?

Answer 13

Simpson’s Paradox (also a confounding variable)

Question 14

What is a randomized control experiment?

Answer 14

-patients should be randomly assigned to either one group that get the new drug or treatment or another group that get the placebo (control)

Question 15

What is a double-blind experiment?

Answer 15

-the patient shouldn’t know whether they’re getting the drug or the placebo (blind)
-the health professionals also shouldn’t know which patients are getting the drug or the placebo (double-blind)

Question 16

What are case-control studies?

Answer 16

-take one sample of people with cases and find another sample of people who do not have cases (control)
-the controls must have other factors the same as the cases so there are no confounding variables

Question 17

What is a historical control?

Answer 17

-compare new procedure to existing data for old procedure

Question 18

What is a longitudinal (or cohort) study?

Answer 18

-data is gathered for the same subjects over a period of time (often many years)

Question 19

What are some difference between case-control studies and longitudinal studies?

Answer 19

-In case-control you can get data right when you want it while in longitudinal you ave to wait for data and people can drop out of the study

Question 20

When you want to study a rare disease which one is better case-control or longitudinal?

Answer 20

Case control because then you do not have to wait to see who will develop the disease

Question 21

What is usually cheaper and quicker case-control or longitudinal?

Answer 21

case-control

Question 22

How do they measure illegal drug use?

Answer 22

self reporting; hospital overdose; police arrests; rehab centers; sewer system

Question 23

How do they measure homeless population?

Answer 23

unsheltered people, police complaints or arrests, divide into sectors and have people count

Question 24

Why is counting and making figures not always obvious?

Answer 24

-there are decisions to make and these decisions matter

Question 25

What are some issues that can arise when you are counting and determining which data is worth including in your sample?

Answer 25

issues with the numerator and issues with denominator