Unit 1: Designing an Experiment or Study

Question 1

Why do we randomize in a study/experiment?

Answer 1

To reduce bias

Question 2

Cluster Sample

Answer 2

Sample that is taken by doing an SRS on clusters and selecting a few entire groups.

Question 3

Bias

Answer 3

When a survey over- or under-estimates some characteristic of the population.

Question 4

Steps of a simulation

Answer 4

1. Assign digits to outcomes
2. Describe random selection/method
3. Describe trials and response variable
4. State conclusion

Question 5

Population

Answer 5

The entire group of individuals about whom we hope to learn.

Question 6

Sample

Answer 6

A (representative) subset of a population.

Question 7

Sample survey

Answer 7

A study that asks questions of a sample drawn from some population.

Question 8

Randomization

Answer 8

The best defense against bias.

Question 9

Sample size

Answer 9

The number of individuals in a sample.

Question 10

Census

Answer 10

A sample that consists of the entire population.

Best used on a small population.

Question 11

Population parameter

Answer 11

A numerically valued attribute of a model for a population.

Question 12

Statistic, sample statistic

Answer 12

Values calculated for sampled data.

Question 13

Simple Random Sample (SRS)

Answer 13

A simple random sample of a sample size, n, which has an equal chance of selection.

Question 14

Stratified random sample

Answer 14

A sampling design in which the population is divided into strata, random samples are then drawn from each stratum.

Question 15

Cluster sample

Answer 15

A sampling design in which entire groups are chosen at random.

Question 16

Systematic sample

Answer 16

A sample drawn by selecting individuals systematically from a sampling frame.

Question 17

Voluntary response bias

Answer 17

Bias introduced to a sample when individuals can choose on their own whether to participate in the sample.

Question 18

Convenience sample

Answer 18

A sample that consists of the individuals who are conveniently available

Question 19

Undercoverage

Answer 19

A sampling scheme that biases the sample in a way that gives a part of the population less representation.

Question 20

Nonresponse bias

Answer 20

Bias introduced when a large fraction of those sampled fails to respond.

Question 21

Response bias

Answer 21

Anything in a survey design that influences responses. Normally found in the wording of the survey questions.

Question 22

Random assignment

Answer 22

To be valid, an experiment must assign experimental units to treatment groups at random. MOST IMPORTANT!!

Question 23

Principles of Experimental Design

Answer 23

Control, Randomize, Replicate, Block

Question 24

Placebo

Answer 24

A treatment known to have no effect

Question 25

Completely Randomized

Answer 25

No blocks or pairs.

Question 26

Blocked

Answer 26

Has blocking/ Strata. Reduces variability.

Question 27

Matched

Answer 27

Before/ After. Comparing results for some group of participants.

Question 28

Blind

Answer 28

Participants do not know the treatment . Used to reduce bias.

Question 29

Double-blind

Answer 29

participants and administrators do not know treatments.

Question 30

Retrospective

Answer 30

Any study done by gathering data that already exists ( In the past).

Question 31

Prospective

Answer 31

Any study done by gathering data in the present ( no treatments).

Question 32

Treatments

Answer 32

Total number of groupings in an experiment