1.1 and 1.2 Overview and Descriptive Statistics

Question 1

Population

Answer 1

the entire group to be studied

you define the population, be precise

Question 2

Parameter

Answer 2

numerical summary of entire population

Question 3

Census

Answer 3

data collected from entire population

Question 4

Anecdote

Answer 4

measure of a single individual (opposite of census, nothing can be learned from it)

Question 5

Sample

Answer 5

subset of the population

* DO NOT give certainty (not 100% accurate)

Question 6

Statistic

Answer 6

numerical summary of a sample

study of designing sampling methods to reduce bias

Question 7

Statistics (inferential statistics)

Answer 7

using info about sample to make inferences about population

Question 8

Probability

Answer 8

knowing something about population (general rule / trend) and applying it to sample

Question 9

Error =

Answer 9

statistic - parameter
(error = difference)
error is NOT the same as mistakes

Question 10

Statistic =

Answer 10

parameter + error

Question 11

sampling error =

Answer 11

chance error

Question 12

nonsampling error =

Answer 12

bias! ex: asking how many students exercise after coming out of the gym

Question 13

Types of Samples

Answer 13

Convenience, Quota, volunteer, Random (simple: equal likelihood, Systematic: every 14th person, Cluster: specific areas, Stratified: random quota), Multistage (combination of a few types) ex pick 5 random dorms, pick every 9th person from each floor

Question 14

Convenience Samples

Answer 14

asking the people the researcher encounters

haphazard != random

Question 15

Quota Samples

Answer 15

convenience with stratification

Ex. 5 men and 5 women

Question 16

Volunteer Samples

Answer 16

voluntary responses
extreme responses (especially negative) think about people's motivation to respond

Question 17

Random Sample

Answer 17

any individual is as likely to be included as any other

• remove bias
• you don’t decide who’s in the sample (chance)

Question 18

Simple Random Sample (SRS)

Answer 18

using a randomizing device to select subjects

-dice, cards, random number table, technology

Question 19

Stratified Random Sample

Answer 19

simple random samples done on each set of partitions of a pop.

• male vs female
• bias if subpopulations are not equal

Question 20

Multi-stage sample

Answer 20

combination of several methods

-randomly select floors and knock on every other door

Question 21

Variables

Answer 21

characteristics of individuals

Question 22

Categorical or Qualitative Variables

Answer 22

they place individuals into distinct groups (categories)

Question 23

Quantitative Variables

Answer 23

numerical measures which ARITHMETIC MAKES SENSE

ex. can’t average zip codes, can average heights

Question 24

Discrete Variables

Answer 24

quantitative variables where possible values have JUMPS
ex. shoe size, can’t have size 4.443
can’t have 32.5 students

Question 25

Continuous Variables

Answer 25

quantitative variables where values can be arbitrarily close ex. temp, distance, height

Question 26

Frequency Distribution

Answer 26

a list of each category of data, and the number of occurrences for each category (frequency: how many things fall into each category)

Question 27

Relative Frequency

Answer 27

percentage of observations in a certain category RF = frequency / total # of observations (what proportion of the whole is in each category)

Question 28

Ways of displaying Categorical Data

Answer 28

Bar graph, pie chart

Question 29

Ways to display Quantitative data

Answer 29

histograms, stem plots, dot plots

Question 30

Histogram

Answer 30

displays data distribution divided into classes -Discrete data: classes = DIFF values (set) -Continuous data: classes = RANGE of values (only one value can be in each class) -classes turn quantitative data into categorical data

Question 31

Stem Plot (stem and leaf plot)

Answer 31

represents quantitative data graphically "( )" = values in stem containing MEDIAN value #items stem #each item in stem ex: 5 1 55678 = 15, 15, 16, 17, 18

Question 32

Dot plot shapes

Answer 32

``` Symmetric: bell curve Skewed Left: bump = right Skewed Right: bump = left Bimodal: 2 bumps Center, spread, outliers ```