Data Analyses Flashcards
Review
What is statistics?
Describes and interprets quantitative information
Aid in making generalization and interferences from data
Mathematical tests are done
At what language does test are used to describe population data?
Greek letters:
- Mean(average) – μ
- standard deviation = σ
- variance = σ2
At what language does test are used to describe data from sample?
English letters:
- Statistics = characteristic at a sample
- Mean (average) = M or (pronounced as X bar)
- Standard deviation= s or sd
- Variance = s^2
Define term:
Parametric statistical test
NOT TO BE CONFUSED WITH POPULATION PARAMETER
Interval or ratio data
Define Term:
Non-parametric statistical test:
Data are counted (nominal scale) or ranked (ordinal scale)
What does it mean to have Normal distribution?
- density curves
- To be considered normal they need to have
— symmetrical
— single peaked
— bell-shaped
By what does the shape of the distribution gets effects?
Mean and standard deviation
68 - 95 - 99
68 % –> observations will fall between the mean and one standard deviation (+/1).
95% –> observations will fall between the mean ad two standard deviation (+/-2).
99.7%–> observations will fall between the mean and three standard deviations (+/-3).
Why don’t standard deviation add up to 100%?
—- The 0.3 % remaining is equal to 0.15% in the each end which represent the extreme scores as such, are relatively rare
What does mean represent in the graph
Skewness- to which direction the graph looks
What does STDV represent in the graph
kurtosis - How steep the graph will be
There are 2 different characteristic of distribution of scores
Central tendency:
- Value of a “typical” score
—- Mean
—- Median
—- Mode
Variability
—- Range
—- Variance
—- Standard deviation
