Measurement Levels Descriptive Analyses Flashcards
The Process of assigning descriptors to represent the range of possible responses to a question about a particular object or construct
Scale Measurement
Degrees of intensity are commonly referred to as
scale points
What so scale measurements assign
degrees of intensity to the responses
What are the four basic scale levels
- Nominal
- Ordinal
- Interval
- Ratio
Nominal Scales
- assign numbers to objects where different numbers indicate different objects
- no other meaning for numbers
What are the properties of Nominal Scales?
- responses don’t contain a level of intensity
- Allows to categorize the responses to labels
- Mutually exclusive categories
- categorical data
- ranking of the set of responses is not possible
- only possible arithmetic: Count the number of responses in each category
What scale assigns numbers to objects, but also give numbers a meaningful order?
Ordinal scale
What are the properties of Ordinal Scales
- Express relative magnitude between the answers to a question
- Responses can be rank-ordered in a hierarchical pattern
- Relationships between responses can be determined by greater than/less than and more often/less often
- Can’t determine absolute differences between rankings
Numbers have order, but there are also equal intervals
between adjacent categories, lacks true zero point
Inverval Scales
What are the properties of Interval Scales?
- Numbers in scale are meaningful and represent equal increments
- Numbers represent not only the hierarchical differences but also the absolute differences
- They lack a true zero point
Division only works with which scale?
Ratio scales
Differences are meaningful, additionally,…
ratios are too
What type of scale should you never divide?
Interval scales
What is measures of central tendency?
An attempt to describe a set of data by identifying the central position
What are the three summary statistics?
- Mean
- Median
- Mode
What is measures of central tendency also classed as?
summary statistics
What is the mean?
The average of a dataset and is affected by outliers.
What is the most comment measurement of central tendency
mean
What is the median
The middle number in a sorted ascending or descending list of numbers and is not affected by outliers.
What is the mode?
Value that occurs most often, is not affected by outliers, and there may not be any modes or may have several modes.
Is measures of central tendency adequate to describe data?
No!
What is dispersion in statistics
The extent to which a distribution is stretched or squeezed
What are the two type of measures of dispersions?
- Range
- Standard Deviation
What is a range?
Difference between the largest and smallest values
What is the simplest measure of dispersion?
Range
What is a variance?
- Measure of how data points differ from the mean and measures how far a set of data (numbers) are spread out from their mean value.
or
- Average of squared deviations of values from the mean
What are the steps of calculating the variance?
- Find the mean of the given data set.
- Now subtract the mean from each value and square them.
- Find the sum of these squared values.
- Divide the sum of squares by n-1.
- The result is the variance.
