Test-retest reliability: are the results of the measurement consistent from one time
to another time?
Interrelater Reliability: is there consistency between individuals' scores on
ratings?
Types of Validity:
Content Validity: whether a measurement tool measures all aspects of a construct
of interest
Criterion-related validity: how well a tool is related to a particular criterion.
Construct validity: extent to which scores of a measurement tool are correlated
with a construct we wish to measure.
Internal validity: whether there is any uncontrolled or confounding variable that
may influence the end result of a study
External validity: whether the results of a study can be generalized beyond the
study itself.
Levels of measurements/ Characteristics
Nominal: Mutually exclusive categories. No ranking or ordering imposed on
categories. Examples: gender, ethnicity, religious affiliation, political party
membership, hair color.
Ordinal: same as above plus ranking or ordering. Mutually exclusive categories.
Ranking or ordering imposed on categories. Examples: Age, letter grade, Likert
type scale, ranking in a race (1
st
, 2
nd
, 3
rd
), histological ratings.
Interval: same as above plus assigned meanings between categories. Mutually
exclusive categories with rankings. Specific meanings applied to the distances
between categories. No absolute zero. Camparison can be made in ratio. Example:
temp. Standardized tests such as IQ, SAT, ACT, TOEFL.
Ratio: same as above jplus meaningful zero and ratio or equal proportion.
Characteristicsof interval level of measurement. Also an absolute zero.
Comparison can be made in ratio. Examples: age, height, weight, income.
Understand
basic meaning of SPSS and its purpose
Grouping Data: Frequency Distribution:
Displays possible values and corresponding frequencies
Provides summative data
Can be either ungrouped or grouped. Ungrouped: suitable for categorical
measurements, nominal or ordinal, and continuous measurements with a small
range of data values. Grouped: suitable for continuous measurements with a large
range of data values. Inserting- Excel: insert tab> Recommended PivotTables.
SPSS: Analyze > descriptive statistics > frequencies.
Displaying/organizing data:
bar chart, histogram, scatter plot, box plot, pie chart.
o
Presentation of the data affects audience understanding
o
Factors to consider: the amount of data to describe, the level of measurement,
audience characteristics.
o
Is the data categorical or continuous? Categorical: bar chart, pie chart or line
chart. Continuous: histogram, stem and leaf plot, boxplot, or scatterplot (2
variables).