stat unit 1

Question 1

Individual

Answer 1

smallest thing that will provide us with data/which data can be collected

Question 2

Variable

Answer 2

any characteristic of interest of an individual

Question 3

Categorical (qualitative) variable

Answer 3

a set of groups or categories

Question 4

nominal level

categorical data

Answer 4

assosciated with words or names

ex. state of residency

Question 5

ordinal level

categorical data

Answer 5

can be classified in a non-numeric order

ex. small, medium, large

Question 6

Numerical (quantitative)

Answer 6

variable defined by a set of numbers

Question 7

interval level

numerical

Answer 7

associated with a range of numbers, but 0 is not clearly defined

ex. temperature 0 degrees C = 32 degrees F

Question 8

ratio level

numerical

Answer 8

can be compared between individuals, zero is clearly defined

Ex. $0 = absence of money

Question 9

population

Answer 9

entire group of individuals

typically very large

Question 10

Sample

Answer 10

portion of population that provides us with data

sample size (N) less than or equal to popoulation

Question 11

Parameter

Answer 11

fixed unknown number describing some characteristic of the popoulation (fixed - stays the same bc population doesnt change, unknown - population is too big to find exact value)

characteristic examples: average, median, std. dev.

Question 12

statistic

Answer 12

a varying and known number describing a characteristic of the sample
- varies with each sample taken from the same population
- used to estimate the perameter

Question 13

observational study

Answer 13

only observe how individuals react within situations the individuals are already in
- researchers have no control over situations
- correlation

Question 14

types of observational studies

Answer 14

surveys and ethical dilemmas
- describe a group or situation by passively collecting data

Question 15

experiments

Answer 15

deliberately impose situations on individuals in order to see what happens
- describe a group or situation by actively collecting data
- cause and effect

Question 16

Cause and Effect

Answer 16

Because of the situaton (imposed by researchers), something happened

Question 17

Correlation

Answer 17

there may be a realtionship between the two, but we cant be certain

Question 18

Bad Sampling Techniques (BST)

Voluntary Response Sample

Answer 18

Individuals participate only because they really care about the topic

Course evaluations, ppl who either love or hate the class participate

Question 19

Bad Sampling Techniques (BST)

Convenience Sample

Answer 19

Individuals participate bc they are easy to contact

Question 20

Simple Random Sample (SRS)

Answer 20

Eliminates sampling bias, like a lottery
- N individuals chosen from the popoulation such that each individual of the populaiton has the same chance of being chosen
- each possible sample size N has the same chance of being chosen

Use table A for problems, 1-9

Question 21

Stratified Sample

good

Answer 21

Divide population into groups (strata) such that all individuals in a group have something in common
- take SRS from within each group
- Ex. pop. = clemson students, strata = freshmen, sophomore, etc, sample = randomly select 500 students from each group
- “some” OR “from each”

Question 22

Cluster Sample

good

Answer 22

Divide population into groups (clusters) such that all individuals in a group have something in common
- take SRS of groups, sample is all individuals within chosen groups
- Ex. pop. = clemson students, clusters = residence halls (bc there are many), sample = randomly select 5 residence halls

Question 23

Systematic Sample

good

Answer 23

• order population in some way
• randomly select a starting individual and a k integer, such that k is greater than 1 and less than the population size
• sample = starting infividual and every Kth individual after that until desired sample size it met

Question 24

Sampling Errors

Answer 24

Use of bad sampling techniques
- fix = change sampling to SRS (stratified, cluster or systematic)

Question 25

Random Sampling Errors

Answer 25

Deviations between statistic and paramters - statistic is consistently smaller/larger than the parameter - fix = increase sample size

Question 26

Non-Sampling Errors

Answer 26

Errors not caused by sampling technique - entire pop. isnt represented accurately = under coverage of a sub-population - erroneous or multiple inclusion = subpop. counted too many times - processing errors = mistake in mechanical tasks - response errors = individual gives incorrect respons - nonresponse = failure to obtain data

Question 27

# observational studies Slanted question

Answer 27

questions can be worded in a way to force a particular response - biased

Question 28

# observational studies confusing words question

Answer 28

words may not be confusing to you but could be to the reader - ex. football

Question 29

2 questions in 1

Answer 29

two questions might not be obvious, which would lead to greater misinterpretation

Question 31

double negatives

Answer 31

confusing to reader

Question 32

properly ordered questions

Answer 32

if one question relies on or can be influenced by the answer from another, then they should be placed in approprate order

Question 33

matching

Answer 33

specific observational study when ethics are involved -**reasearchers dont control anything**

Question 34

# Experiments Response Variable (RV)

Answer 34

dependent variable - what we are hoping to see a change in - measures outcome or result

Question 35

# experiments Explanatory Variavle (EV)

Answer 35

independent variable - explains or causes change in the response variable

Question 36

# experiments Subject (S)

Answer 36

individuals studied in an experiment - subject = single thing studied in experiment - individual - single thing studied in an observational study

Question 37

# experiments treatment (T)

Answer 37

any specidic experimental condition applied, by the researchers, to the subject - specific levels of the explanatory variable - EV are general, these are **specific**

Question 38

# experiment Lurking Variable

Answer 38

Characteristic that affects the RV but is not included as an EV -** inevitable** -poorly designed experiment

Question 39

Confounded

Answer 39

two variables when their effects on an RV cannot be distinguished from one another

Question 40

Randomized Comparative Experiment (RCE)

Answer 40

designed in a way so that the treatments can be compared

Question 41

Double-Blind Experiment (DBE)

Answer 41

Neither the subjects nor the experimenters know which treatment each subject is recieving

Question 42

# principles of experimental design control

Answer 42

effects of lurking variables on the response variable by ensuring all subjects are affected by any lurking variables

Question 43

# principles of experimental design Randomize

Answer 43

Assigment of subjects to the treatments to ensure the groups are as similar as possible

Question 43

# principles of experimental design Use enough subjects

Answer 43

in each group to reduce chance variation in the results

Question 44

# experimental designs Completely Randomized Design (CRD)

Answer 44

All subjects are randomly distributed to the treatments -hope to get the same number of subjects in each treatment group but not always possible

Question 45

# experimental designs Matched Pairs Design (MPD)

Answer 45

put subjects into pairs so that they are as similar as possible - treatments are randomly assigned within each *pair * - only two treatments - sometimes each pair is a single subject who gets both treatments and the order of treatments is randomized

Question 46

# experimental designs Block Design (BD)

Answer 46

groups of similar subjects are put into "blocks" - randomly assign treatments within each block - Conclusion made for each embedded CRD, not one conclusion combining the infor - based on most significant *unavoidable sources of variability* (gender, age, etc)