A research perspective which states there will be no true difference between the groups being compared.
Three attributes that differ between nominal/ordinal/interval/ratio data.
Order/magnitude, spacing/scale, rational absolute zero
Does nominal data have magnitude? Does nominal data have a consistent scale?
Does ordinal data have magnitude? Does ordinal data have a consistent scale?
Yes (i.e. it can be ordered); No (example = satisfaction survey)
Does interval/ratio data have magnitude? Does interval/ratio data have a consistent scale?
Yes; Yes (Tigger/Buzz = Units)
True/False: After data collection you can move up (i.e. nominal => ordinal => interval => ratio) is specificty.
False, you may only move down
Average of the squared-differences in each individual measure value (x) and the groups' mean.
Square root of variance value
In a normal distribution curve the first standard deviation represents how much of the data?
In a normal distribution curve the second standard deviation represents how much of the data?
In a normal distribution curve the third standard deviation represents how much of the data?
Statistical test useful for normally-distributed data.
Parametric (i.e. associated with interval/ratio data)
Data distribution, asymmetrical, mean > median, tail points right
Data distribution, asymmetrical, mean < median, tail points left
Skewness value of 0.
Symmetrical data distribution (i.e. not skewed)
Positive skewness value.
Negative skewness value.
Numerical value that evaluates how aggregated a data set may be (i.e. how clusted the data is)
Kurtosis (i.e. + = more cluster)
Four key questions for selecting the correct statistical test.
- What data level is being recorded? (i.e. nominal, ordinal, interval/ratio)
- What type of comparison/assessment is desired?
- How many groups are being compared?
- Is the data independent or related/paired?
Buzz words for correlation statisical test.
Correlation, association, relationship
Buzz words for regression statistical test.
Prediction, association, relationship.
Statisical test that derives a quantitative measure of strength and direction between the relationship of two variables.
Nominal correlation test.
Ordinal correlation test.
Interval/ratio correlation test.
A correlaiton that controls for confounding variables (i.e. only for interval data)