Stats M. 5

Question 1

Census

Answer 1

obtain information from the entire population of interest

Question 2

sampling

Answer 2

obtain information from a subset of the population of interest

Question 3

designed experiment

Answer 3

researchers assign subjects to a certain group, intentionally change the conditions of each group, and record the value of the response variable for each group
-establishes causation

Question 4

observational study

Answer 4

researchers observe characteristics and take measurements
-recorded in natural settings
-only reveal association or correlation (NOT causation)

Question 5

sampling frame

Answer 5

list of all of the members of a population that can be sampled

Question 6

sampling method

Answer 6

the process used to obtain a sample

Question 7

random sampling

Answer 7

employs a random device to select the sample

Question 8

Simple random sampling

Answer 8

each possible sample of a given size has the same chance of being selected
-with or without replacement
-randomly select 10 employees from a company of 250 employees

Question 9

Stratified random sampling

Answer 9

split the population into subgroups that share a similar characteristic and take a sample from each subgroup
-splitting band up into woodwinds, brass, percussion, and string sand taking a random sample from each subgroup

Question 10

systematic random sampling

Answer 10

use a pattern to determine which members of the population are included within the sample
-to check the accuracy of an ice cream machine, every 500th. container is selected a weighed

Question 11

cluster random sampling

Answer 11

we split the population into diverse sections and take a census from randomly selected sections and nothing from others
-in a medical research study, a researcher randomly selects hospitals and then interviews all the patients at the selected hospitals from that day

Question 12

treatment

Answer 12

experimental condition (manipulated by the researcher)

Question 13

experimental unit

Answer 13

subjects within the experiment that receive treatment (including no treatment from the control group)

Question 14

treatment group

Answer 14

groups that receive the treatment (experimental condition)

Question 15

control group

Answer 15

group that participates in the experiment and whose treatment is “nothing”

Question 16

placebo

Answer 16

a “fake” treatment that looks just like the treatments being tested
-keep subjects who are in the control group from knowing they are in the control group

Question 17

placebo effect

Answer 17

subjects treated with a placebo sometimes improve even though they are not receiving an actual treatment

Question 18

single blind

Answer 18

subjects don’t know which group they are in

Question 19

double blind

Answer 19

subjects and collectors don’t know which groups the subjects are in

Question 20

randomization

Answer 20

randomly assign subjects to treatment groups
-eliminates bias

Question 21

replication

Answer 21

apply each treatment to a number of subjects
-repeat the entire experiment at different levels of the treatment

Question 22

control

Answer 22

make conditions as similar as possible for all treatment groups

Question 23

blocking

Answer 23

group similar individuals together and then randomly assign treatments within each of the blocks

Question 24

convenience sample

Answer 24

include individuals who are easy to sample and therefore may not represent population
-standing outside Armstrong and asking students questions

Question 25

volunteer sample

Answer 25

made up of people who self-select into the survey
-not representative of the population
-follow up questionnaires received via email after visiting doctors

Question 26

under coverage

Answer 26

occurs when the sampling frame foes not represent all parts of the population f

Question 27

over coverage

Answer 27

occurs when members that are not in the population of interest are included in the sample

Question 28

non response bias

Answer 28

some sampled subjects cannot be reached or refuse to participate

Question 29

response bias

Answer 29

wording of a question is confusing or misleading or subjects lie because they think their response is socially unacceptable