Ch. 1 Data Collection

Level of measurements

1. nominal 2. ordinal 3. interval 4. ratio

Discrete variable

A quantitative variable that has either a finite number of possible values or a countable number of possible values.

______ statistics consists of organizing and summarizing info collected, while ______ statistics uses method that generalize results obtained from a sample to the population and measure the reliability of the results.

Descriptive, Inferential

A _______ is a person or object that is a member of the population being studied.

Individual

Parameter vs Statistic

Parameter is a summary of a POPULATION. Statistic is a summary of a SAMPLE.

Convenience

Sample is a sample in which the individual are easily obtained.

Stratified

Sample is obtain by separating the population into nonoverlapping groups and then obtaining a simple random sample from each group.

Systematic

Sample is obtained by selecting every _th individual from the population ( the first individual selected is a random number from 1 to X).

Cluster

Sample is obtained by selecting individuals within a randomly selected group of individuals.

What is Statistics?

Statistics is the science of collecting, organizing, summarizing, and analyzing information to draw a conclusion and answer questions. In addition, statistics is about providing a measure of confidence in any conclusions. 1. collection of info. 2. organization and summarization of info. 3. analyze info to draw conclusion or answer specific questions. 4. results should be reported with some measure that represent how convinced we are that our conclusion reflect reality.

The Gallup Organization contacts 1014 teenagers who are 16 to 19 years of age and live in North America and ask whether or not they had driven a care on a highway recently. What is the population in the study?

Teenagers who are 16 to 19 years of age and live in North America.

The Gallup Organization contacts 1014 teenagers who are 16 to 19 years of age and live in North America and ask whether or not they had driven a care on a highway recently. What is the sample in the study?

The 1014 teenagers who are 16 to 19 years of age and live in North America.

_____ are the characteristics of the individuals of the population being studied.

Variables

Continuous variable

a quantitative variable that has an infinite number of possible values that are not countable. A continuous variable may take on every possible value between any two value.

Qualitative variables

allow for classification of individuals based on some ATTRIBUTE or CHARACTERISTIC.

Ratio level

has the properties of Interval and the ratios of the values of the variable have meaning. A VALUE OF ZERO MEANS THE ABSENCE OF THE QUANTITY.

Ordinal level (order)

if it has the properties of the nominal level of measurement, however the naming scheme allows for the values of the variable to be arranged in a ranked or specific order.

Interval level

if it has the properties of the ordinal level and the differences in the values of the variable have meaning.

Nominal level (name)

if the values of the variable name, label, or categorize.

Designed experiment

is when a researcher assigns individuals to a certain group, intentionally changes the value of an explanatory variable, and then records the value of the response variable for each group.

Observational study

observational study measures the value of the response variable without attempting to influence the value of either the response or explanatory variables. *Observational studies do not allow a researcher to claim causation, only association.

A _____ is a numerical summary of a population.

parameter

Quantitative variable

provides numerical measures of individuals. The values of a quantitative variable can be added or subtracted and provide meaningful results.

Simple random

sample has each possible sample of a given size is equally likely to occur.

Explain what is meant when it is said that "data vary." How does the variability affect the results of statistical analysis?

saying "data vary" means that the values of the variable change from individual to individual. In addition, certain variables can change over time for certain individuals. Because data vary, two different statistical analysis of the same variable can lead to different results.

a _____ is a numerical summary of a sample.

statistic