Statistical Analysis

* Organize data
*  Infer from sample to population
* Must be familiar with to read articles and interpret basic test information
* Observations into numbers

Types of Data
•        Nominal
•        Ordinal
•        Interval
•        Ratio
•        Used to determine the appropriate statistical analysis and type of data.

Nominal Data
•        Place in categories
•        Mutally exclusive
•        Numbers must be exclusive
–          0 = males  1 = females
•        Count the # of observations or percentage of observations

Ordinal Scale
•        Ranks objects or individuals
•        How much or how little
–          If A>B and B>C then A>C
•        Greater than more than
•        Direct comparison in terms of attribute
•        Rank 1-2-3-4-5
•        The distance can vary

Interval Scale
•        More Precise
•        Orders objects according to amount of attribute
•        Equal intervals
•        Equal differences
•        Order & distance have meaning
•        No true zero point

Ratio Scale
•        Highest Level
•        True zero point
•        Equal intervals
•        Physical and Motor Performance

Mode
•        Represents Most Often
•        18, 19, 20,21,21,22,23,24,
–          Mode = 21
•        18,19,20,20,21,21,22,23,24
–          Mode = 20 & 21 Bimodal

Mode
•        Not a stable measure
•        Two modes from different populations are often different
•        Seldom reported
•        Used with Nominal Data

Median
•        50% cases above and below
•        10, 15,  20,  25, 30
•        Median = 20
Relates to middle. Must put numbers in order   (low to high or high to low).

Median
•      50% cases above and below
•      10, 11, 12, 13, 14, 15
•      Median = 12.5
•      Ordinal statistic based on rank order

MEAN = sum of score : N

Type Scores
•        Mean = Interval or ratio
•        Median = Ordinal Statistic
•        Mode = Nominal
•        Mean is more stable
–          Means will vary less than median or mode
–          More frequently used
–          Best indicator of combined performance of entire group
•        Median = typical performance

Learning Objectives
•        Know the following:
–          Types of data and how used (nominal, ordinal, interval, ratio)
–          Descriptive statistics (Measures of Central Tendency – mean, median, mode)
–          How to calculate descriptive statistics