Statistics Chapter 1

Front 1

statistics

Back 1

a collection of methods for planning studies and experiments, obtaining data and then organizing, summarizing, presenting, analyzing, interpreting and drawing conclusions drawn by the data

Front 2

descriptive statistics

Back 2

used to reveal patterns through analysis of numeric data

Front 3

inferential statistics

Back 3

used to draw conclusions and makes predictions based on analysis of numeric data

Front 4

sample

Back 4

the subcollection of data of the population

ex. minorities in the U.S.

Front 5

population

Back 5

the collection of data from everyone

ex. the entire state of N.Y.

Front 6

statistic vs. parameter

Back 6

parameter deals with population, statistic deals with sample

Front 7

difference in notation of statistic vs. parameter

Back 7

sample uses Roman letters (or lower case) and population uses Greek letters (or upper case)

Front 8

why do we collect data from a sample instead of a population?

Back 8

because it is easier to construct a generalization about a population rather than going to try and contact every single person.

It is nearly impossible to get everyone in a population

Front 9

main goal when selecting a sample

Back 9

make inferences about an entire population

Front 10

simple random sample

Back 10

a randomly chosen subset of a population. The sample is chosen randomly.

ex. taking 20 people and picking 5 out of a hat for a study. Subjects are selected in such a way that every possible sample of the same size has the same chance of being chosen

Front 11

4 types of sampling methods

Back 11

systematic sampling
convenience sampling
stratified sampling
cluster sampling

Front 12

systematic sampling

Back 12

when a starting point is selected and every x is recorded in population

ex. taking 1st student in an entire grade than every 10th person

Front 13

convenience sampling

Back 13

using results that are very easy to get

ex. walking into a room and seeing how many males : females and making an assumption of a school on that

Front 14

stratified sampling

Back 14

subdivide the population into at least 2 groups so that subjects in same groups share some characteristics
the sample is drawn from each subgroup

ex. putting people into groups based on eye color then draw a sample from each group

Front 15

cluster sampling

Back 15

first divide the population area into sections then randomly select some of the clusters and then choose all members from selected clusters

ex. divide number of counties in a state then select a random county then interview all the members of the county

Front 16

observational study

Back 16

the observation and measure of specific characteristics without modifying subjects being studied

ex. a gallop poll is observation of people without modifying them

Front 17

experiment

Back 17

the subjects are slightly modified and the effects are observed

ex. a clinical trial of a drug

Front 18

confounding variable

Back 18

when during an experiment a person is not able to distinguish among effects or different factors

Front 19

categorical data

Back 19

data that is separated into different categories that are distinguished by some non-numeric characteristic

ex. genders of professional athletes

Front 20

numerical data

Back 20

data that consists of numbers representing counts or measurements

ex. weight of supermodels

Front 21

discrete data

Back 21

whole numbers

ex. the number of eggs a hen lays

Front 22

continuous data

Back 22

amounts or measurements

ex. the amount of milk from cows

Front 23

quantitative data

Back 23

consists of numbers representing counts of measurements

Front 24

qualitative data

Back 24

the genders (male/female) of professional athletes

Front 25

nominal level of measurement

Back 25

characterized by data that consist of names, labels, or categories only.

the data cannot be arranged in an ordering scheme (such as low to high)

ex. yes, no or undecided

Front 26

interval level of measurement

Back 26

like the ordinal level, with the additional property that the difference between any two data values is meaningful

data at this level does not have a natural zero starting point (where none of the quantity is present)

Front 27

ratio level of measurement

Back 27

the interval level with the additional property that there is also a natural zero starting point (where zero indicates that none of the quantity is present)

for values at this level, differences and ratios are both meaningful

Front 28

voluntary response sample
or self-selected sample

Back 28

a sample in which the respondents themselves decide whether to be included

Front 29

cross-sectional study

Back 29

data are observed, measured, and collected at one point in time

Front 30

retrospective study
or case-control study

Back 30

data are collected from the past by going back in time (through examination of records, interviews, and so on)

Front 31

prospective study
or longitudinal or cohort

Back 31

data are collected in the future from groups sharing common factors (called cohorts)

Front 32

block

Back 32

a group of subjects that are similar

Front 33

replication

Back 33

repetition of an experiment on sufficiently large groups of subjects