Key concepts

Survey method in which groups (clusters) of sampling units (and not individual units) are selected from a population for analysis.

In an experiment, the dependent variable is the event expected to change when the independent variable is manipulated. In data mining tools, the depending variable is assigned a role as target variable (or in some tools as label attribute), while a dependent variable may be assigned a role as regular variable. The dependent variables represent the output or outcome whose variation is being studied.

-The standard survey rating scale.

-Equidistant points between each of the scale elements (have differences in the distance along the scale). We contrast this to an ordinal scale where we can only talk about differences in order, not differences in the degree of order.

 E.g: use interval scale to rate people satisfaction, on a 7 point scale, from Dissatisfied to Satisfied.

-A scale which are defined by metrics such as logarithms (the distances are note equal but they are strictly definable based on the metric used).

statistics: 

Interval scale data mostly use parametric statistical techniques:

 -Mean and standard deviation

 -Correlation

 -Regression

 -Analysis of variance

 -Factor analysis

The Freedictionary give the definition of nominal scale as "statistics a discrete classification of data, in which data are neither measured nor ordered but subjects are merely allocated to distinct categories: for example, a record of students' course choices constitutes nominal data which could be correlated with school results."

- It is the lowest measurement that researchers can use.

-place data into categories with no order or structure.

-YES/NO scale.( no order & distance between Yes/No )

statistics:

The statistics which can be used with nominal scales are in the non-parametric group:

-mode

-crosstabulation

-chi-square

Quota sampling means to take a very tailored sample that’s in proportion to some characteristic or trait of a population. 

A sampling method in which all members of a group (population or universe) have an equal and independent chance of being selected.

 It’s called snowball sampling because (in theory) once you have the ball rolling, it picks up more “snow” along the way and becomes larger and larger. Snowball sampling is a non-probability sampling method. It doesn’t have the probability involved, with say, simple random sampling (where the odds are the same for any particular participant being chosen). Rather, the researchers used their own judgment to choose participants.

A method of choosing a random sample from among a larger population. The process of systematic sampling typically involves first selecting a fixed starting point in the larger population and then obtaining subsequent observations by using a constant interval between samples taken. Hence, if the total population was 1,000, a random systematic sampling of 100 data points within that population would involve observing every 10th data point.