basic statistic in technology and assessment mary l. putman

Basic Statistic

in

Technology and AssessmentMary L. Putman

Levels of Measurement

Ordinal LevelInterval LevelNominal LevelRatio 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


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


Interval LevelMore precise measure; calculations meaningful

Provides equal difference in characteristic being assessed

Zero point is arbitrary

Example: Temperature Cognitive Measures (i.e. -- I.Q. Test)


Ratio LevelMost precise and useful level Absolute zeroRatio number can make statements such as … Twice as big/ .. Twice as fast

Examples: Distance throwSpeed run

1. Numbers on a football jersey.

2. Timed scores for 100 meter dash.

3. Mr. RU, first place runner up.

4. Gender classification for M/F.

5. Speedometer reading of 60 mph.

6. Temperature of 32 degrees

7. Wrestler’s height and weight.

Measures of Central Tendency

ModeScore that occurs most often

MedianThe point at which half the scores fall

above and below

MeanThe 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

CorrelationYou 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.)

DirectionThe 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


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)


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 = high correlation .60 to .79 = moderately high correlation .49 to .59 = moderate correlation .20 to .39 = low correlation .00 to .19 = 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.)

MeasurementThe process/procedures used to collect the

data (scores)

EvaluationWhat you do with the information, what

conclusion you reach once the data is analyzed, what action do you take?

basic statistic in technology and assessment mary l. putman

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