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
–
Advantages and disadvantages