Download Basis Statistics PPT

Basic Statistics
in
Technology and Assessment
Levels of Measurement
Ordinal Level
 Interval Level
 Nominal Level
 Ratio Level

Levels of Measurement (cont.)
Nominal Level
Simplest and least precise
Differentiates attribute or property
Little statistical value
Examples:


Locker Number #20
Social Security Number
Levels of Measurement (cont.)
Ordinal Level
Has the property of order (rank)
Indicates difference (more or less)
Indicates direction of difference
Not mathematically meaning
Examples:


Team rankings
Class rankings
Levels of Measurement (cont.)
Interval Level
More precise measure; calculations meaningful
Provides equal difference in characteristic being
assessed
Zero point is arbitrary
Example:
 Temperature
 Cognitive Measures (i.e. -- I.Q. Test)
Levels of Measurement (cont.)
Ratio Level
Most precise and useful level
Absolute zero
Ratio number can make statements such as
… Twice as big/ .. Twice as fast
Examples:
 Distance throw
 Speed run
1.
2.
3.
4.
5.
6.
7.
Numbers on a football jersey.
Timed scores for 100 meter dash.
Mr. RU, first place runner up.
Gender classification for M/F.
Speedometer reading of 60 mph.
Temperature of 32 degrees
Wrestler’s height and weight.
Measures of Central Tendency
Mode

Score that occurs most often
Median

The point at which half the scores fall
above and below
Mean

The numerical average.. The sum of the
scores divided by N (the number of scores)
Measures of Variability
Range

The difference between the highest score and
lowest score
Standard Deviation



The most common measure of variability
Spread of scores
Amount each score deviates from the mean
Measure of Relationship
Correlation

You must have two sets of scores for each
individual in order to use the correlation

Identifies the direction and strength of the
relationship between two sets of scores.
The scores will range from +1.00 to –1.00
Measure of Relationship (cont.)
Direction

The direction is identified by a + or – sign
 + .. Both sets of scores have the higher
score as the better score or lower score
the better score.
 - .. One set of scores the higher score is
better, the other set of scores the lower
score
Measure of Relationship (cont.)
Examples of Direction of Relationship





Twelve minute walk run to Shuttle Run
Golf Score to Upper Body Strength
Over GPA to Grade in Technology/Assess
GPA to SAT
Stress Test (high =more stress) to Obesity
(BMI = higher means fatter)
Measure of Relationship (cont.)
Strength (correlation coefficient)


Number will range from 1.00 to .00
The closer to one the number is the stronger the
relationship
Ranges:





.80 to 1.00
.60 to .79
.49 to .59
.20 to .39
.00 to .19
= high correlation
= moderately high correlation
= moderate correlation
= low correlation
= no relationship
Terminology
Subjects

People participating in your research project
Variables

What you are measuring… speed, body
composition, stress
Test/Assessment

The instrument you are using to collect the data in
your research area.
Terminology (cont.)
Measurement

The process/procedures used to collect the
data (scores)
Evaluation

What you do with the information, what
conclusion you reach once the data is
analyzed, what action do you take?