AP STAT REVIEW: Sampling/Experiments

5.0(1)
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/25

flashcard set

Earn XP

Description and Tags

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

26 Terms

1
New cards
Observational Study
Observing with no treatment
2
New cards
Experiment
Imposing treatment
3
New cards
What does a larger sample size do?
Reduces variability when the sampling design is NOT flawed
4
New cards
Nonresponse bias
Selected people do not respond
5
New cards
Undercoverage Bias
Systematically excluding people from being able to be selected
6
New cards
Response Bias
Providing inaccurate responses (on purpose or by accident)
7
New cards
Wording Bias
Confusing wording or question is slanted towards a particular response
8
New cards
Stratified Random Sample
Division of a population into separate groups (strata) based on shared attributes (homogeneous grouping), SRS is done to select people within the strata, and those units are combined to form the sample.
9
New cards
Experimental unit
Used when an experiment is not performed on humans, but on animals or objects
10
New cards
Subjects
Used when an experiment is done on humans
11
New cards
Confounding Variable
Variable that is related to the explanatory variable and influences the response variable, makes it challenging to determine cause and effect
12
New cards
What should a well-designed experiment include?

1. Comparisons of at least 2 treatment groups (one could be a control)
2. Random assignment of treatments to experimental units
3. Replication: enough experimental units in each treatment group to be able to detect a difference
4. Control of a potential confounding variables where appropriate
13
New cards
Bias
Systematic tendency to overestimate or underestimate the true population parameter
14
New cards
Randomized Block Design
Treatments are assigned completely at random within each block. For each block individuals are similar to one another with respect to at least one blocking variable
15
New cards
Benefits of Block Design
reduce variability of results within each treatment group and eliminate possibility of the blocking variable as the confounding variable
16
New cards
Can results be generalized to a larger population
Yes, but only to the population that the subjects/units were randomly selected from
17
New cards
What are two poor sampling methods?
Convenience sampling and voluntary response sampling (neither uses chance to select individuals)
18
New cards
Simple Random Sample (SRS)
A sample in which every group of a given size has an equal chance of being chosen
19
New cards
How to obtain an SRS
number individuals, use a random # generator/table/draw from hat to select which to include in study (excluding repeats)
20
New cards
Control Group
collection of experimental units that are either not given a treatment of interest or given a treatment with an inactive substance (placebo).
21
New cards
Purpose of control group
Provide a baseline for comparison
22
New cards
Explanatory Variable
a variable whose levels are intentionally maipulated
23
New cards
Response Variable
an outcome from the experimental units that is measured after the treatments have been administered
24
New cards
Completely Randomized Design
Treatments are randomly assigned to experimental units, tends to create roughly equivalent groups so that differences in responses can be attributed to the treatments
25
New cards
Matched Pairs Design
Special randomized block design, each pair receives both treatments by randomly assigning one treatment to one member and the remaining to the other, or both subjects get both treatment
26
New cards
Systematic Random Sample
members from a population are selected according to a random starting point and a fixed, periodic interval, (like every 5th person)