stats chapter 1.1, 1.2, 1.3

stratified random sampling

a few members from each group (stratum) are selected ex: A scientist chooses twenty people at random from each math class. ex:First, the population is subdivided by city. Then a political strategist uses a random number generator to select fifty members from each city to study.

cluster sampling

all members from a few randomly chosen clusters (or groups) are selected ex: A school administrator interviews each member from each of the ten randomly chosen neighborhoods throughout a city. A pollster interviews each member from each of the fifteen randomly chosen neighborhoods throughout a city. -A random number generator is used to choose fifty districts. Then a biologist collects data from each person in these districts.

Nominal level

any order at all, not any certain order. in general, a list of items

sample statistic

are numerical descriptions of sample characteristics

continous data

are quantitative data that can take on any value in a given interval and are usually measurements. (generic measurements)

discrete data

are quantitative data that can take on only particular values and are usually counts

Data

are the counts, measurements, or observation gathered about a specific variable in a population in order to study it

quantitative data

consist of counts or numbers

qualtative data

consist of label, categories, or descriptions of traits

cross sectional study

data are collected at a single point in time

longitude study

data are gathered by following a particular group over a period of time

simple random sampling

every group has the same chance of being selected

Systematic sampling

every n th member of the population is selected

experiment

generates data to help identify cause and effect relationships

Parameter

is a numerical description of a population characteristic

Population

is a particular group of interest

Census

is a study in which data are obtained from every member of the population ex:For budget purposes, a college president needs to know the average cost of health plans of employees at their school.

meta-anaylsis

is a study that complies information from previous studies

Sample

is a subset of the population from which data are collected

variable

is a value or characteristic that changes among members of the population

descriptive statistics

it gathers, sorts, summarizes, and displays the data (actual data)

ordinal level

list of items ranked in a certain order -grocery list of items ranked in order -list of teams ranked according to record -any rating system

case study

looks at multiple variables that effect a single group

Ratio level

numbers which represent an accumulation of values -zero is an inherent (meaningful) value. Ex; points scored on the test, points in a game

inferential statistics

numerical data that allow one to generalize- to infer from sample data the probability of something being true of a population (judgement conclusion estimate)

observational study

observes data that already exist

random sampling

one item is selected from the group. all items have same chance of selection

Interval level

referred to a position on a scale -numbers on a scale -Zero (0) has no inherent value-mostly a position on a scale Ex: years, temperature, a point in time

convenience sampling

the sample is chosen because it is convenient for the researcher