Descriptive Statistics and Interpretation

Descriptive Statistics and Interpretation Example

 

Interpretation Phrases

Central Tendency:

Mean = average of a set of data

Median = half or equal number of data is above and half or equal number of data is below. It is a midpoint in an ordered (sorted) set of data, a physical location

Mode = most frequent value in a set of data

Dispersion:                                                                     

Standard deviation = variation

Interquartile range (IQR) = the middle 50% of the data

Range = the difference between the largest and smallest value of the data

Confidence Interval: (data must be normal)

There is 95% confidence that the population average is between _____ and ____ units.

Normal or significantly skewed data:

MegaStat: Descriptive statistics Normal curve goodness of fit p-value

• Normal, p-value > .05
• Significantly Skewed, p-value < .05

Histogram: Eyeball the histogram.

• Normal data will have a symmetrical or slightly skewed shape.
• Significantly Skewed shape will have extreme skewness

Use phrase combinations:  Normally distributed: Mean and Standard Deviation, Not normally distributed: Median and IQR

 

 

 

 

 

 

 

 

 

 

Descriptive Statistics

Body Weight (Lbs.)

Central Tendency:	Mean = 149 Lbs.
Dispersion:	Standard deviation = 30 Lbs.
Count:	100
Min/Max:	99 pounds and 234 Lbs.
Confidence Interval:	144 to 155 Lbs.

See the histogram in Appendix A, and descriptive statistics in Appendix B.

Age

Distribution is not normally distributed

Central Tendency:	Median = 36 years
Dispersion:	Interquartile Range = 20.5 years / 2 = ± 10 years
Count:	100
Min/Max:	18 years and 74 years
Confidence Interval:	Not applicable (data is not normally distributed)

See the histogram in Appendix A, and descriptive statistics in Appendix B. A scatter plot is in Appendix C.

Education Level

Thirteen percent of the subjects have no high school degree while 44% have high school degree. Forty three percent have a college or college graduate degree. See the bar chart in Appendix D.