Ch 4 Section 1

Question 1

Population

Answer 1

entire group of individuals we want information about

Question 2

Census

Answer 2

collects data from every individual in the population

Question 3

Sample

Answer 3

subset of individuals in the population from which we actually collect data

Question 4

Convenience Sample

Answer 4

choosing individuals from the population who are easy to reach results
ex. people in the mall

Question 5

Voluntary Response Sample

Answer 5

consists of people who choose themselves by responding to a general invitation
Ex. people calling in to a radio station

Question 6

Bias

Answer 6

consistently underestimate or consistently overestimate the value you want to know

Question 7

Which two samples are almost always guaranteed to show bias?

Answer 7

convenience and voluntary response sample

Question 8

Random sampling

Answer 8

using a chance process to determine which members of a population are included in the sample

Question 9

simple random sample (SRS)

Answer 9

size n is chosen in such a way that every group of n individuals in the population has an equal chance to be selected as the sample

Question 10

Stratified random sample

Answer 10

start by classifying the population into groups of similar individuals, called strata. Choose a separate SRS in each stratum & combine these SRSs to form the sample
Ex. Homeroom
Some from all

Question 11

Cluster Sample

Answer 11

start by classifying the population into groups of individuals that are located near each other, called clusters. Choose an SRS of the clusters. All individuals in the chosen clusters are included in the sample
EX. lunch, (all mixed)
(All from some)

Question 12

Undercoverage

Answer 12

occurs when some members of the population cannot be chosen in a sample
Ex. Polaris juniors have no chance to be selected from the sample taken at lunch

Question 13

Nonresponse

Answer 13

occurs when an individual chosen for the sample can not be contacted or refuses to participate
Ex. absent in homeroom or doesnt participate

Question 14

How to choose an SRS (3 ways)

Answer 14

1. Hat, MIX UP names and have equal sized paper
2. Technology, randInt(1,26) IGNORE REPEATS
3. Random digit table

Question 15

What type of groups are in clusters vs stratified?

Answer 15

cluster sample- heterogeneous groups (differences within the group, same outside the group)
stratified- homogeneous groups (similarities (same opinion) within the group, different outside the group)

Question 16

most common sample?

Answer 16

Stratified random sample