Exam 3 - Biostatistical Tests Flashcards
A research perspective which states there will be no true difference between the groups being compared.
Null hypothesis
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?
No; No
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)
Black
Nominal
Red
Ordinal
Orange
Interval
Yellow
Ratio
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.
Variance
Square root of variance value
Standard deviation
In a normal distribution curve the first standard deviation represents how much of the data?
68%
In a normal distribution curve the second standard deviation represents how much of the data?
95%
In a normal distribution curve the third standard deviation represents how much of the data?
99.7%
Statistical test useful for normally-distributed data.
Parametric (i.e. associated with interval/ratio data)
Data distribution, asymmetrical, mean > median, tail points right
Positively skewed
Data distribution, asymmetrical, mean < median, tail points left
Negatively skewed
Skewness value of 0.
Symmetrical data distribution (i.e. not skewed)
Positive skewness value.
Positively skewed
Negative skewness value.
Negatively skewed
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.
Correlation
Nominal correlation test.
Contingency Coefficent
Ordinal correlation test.
Spearman Correlation
Interval/ratio correlation test.
Pearson correlation
A correlaiton that controls for confounding variables (i.e. only for interval data)
Partial correlation
A correlation test, shows relationship of agreement between/consistency of “decisions”.
Kappa statistic