Definities

(uit elementary statistics)

Parameter/Statistic

A parameter ==> a numerical measurement describing some characteristic of a population.
A statistic     ==> numerical measurement describing some characteristic of a sample.

HINT The alliteration in “population parameter” and “sample statistic” helps us remember the meaning of these terms.

 

Quantitative/Categorical

Quantitative (or numerical) data   ==> consist of numbers representing counts or measurements.

Categorical (or qualitative or attribute) data  ==> consist of names or labels that are not numbers representing counts or measurements.


Discrete/Continuous

Quantitative data can be further described by distinguishing between discrete and continuous types. Discrete data ==>  result when the data values are quantitative and the number of values is finite or “countable.” (If there are infinitely many values, the collection of values is countable if it is possible to count them individually, such as the number of tosses of a coin before getting tails.)

Continuous (numerical) data ===>  result from infinitely many possible quantitative values, where the collection of values is not countable. (That is, it is impossible to count the individual items because at least some of them are on a continuous scale, such as the lengths from 0 cm to 12 cm.)

nominal, ordinal, interval, and ratio

The nominal level of measurement is 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).
bijv Yes/No/Undecided: Survey responses of yes, no, and undecided

Data are at the ordinal level of measurement if they can be arranged in some order, but differences (obtained by subtraction) between data values either cannot be determined or are meaningless.
bijv Course Grades: A college professor assigns grades of A, B, C, D, or F. These grades can be arranged in order, but we can’t determine differences between the grades.

Data are at the interval level of measurement if they can be arranged in order, and differences between data values can be found and are meaningful. Data at this level do not have a natural zero starting point at which none of the quantity is present.
bijv Body temperatures in degrees Fahrenheit or Celsius

Data are at the ratio level of measurement if they can be arranged in order, differences can be found and are meaningful, and there is a natural zero starting point (where zero indicates that none of the quantity is present). For data at this level, differences and ratios are both meaningful.

bijv  Heights, lengths, distances, volumes

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