Measurement Exam 1 Flashcards
Descriptive Statistics
Concerned with the presentation, organization, and summarization of SAMPLE DATA
Inferential Statistics
Allows us to generalize or make inferences from our sample of data to a larger group of subjects
Discrete Variable
- can have only one of a limited set of values or only whole numbers
- ex. gender, amount of hospitalizations
Continuous Variable
- may take an infinite number of values within a given range
- ex. age, temperature, weight
NOIR
- Nominal
- Ordinal
- Interval
- Ratio
Nominal Scale
- named categories, with no implied order among the categories
- ex. gender, Y/N, political party
Ordinal Scale
- ordered categories, where the differences between categories cannot be considered to be equal
- ex. grades, pain scale
Interval Scale
- equal distance between values, but the zero point is arbitrary
- ex. temperature
Ratio Scale
- equal intervals between values and a meaningful zero point, which represents absence of the characteristic being measured
- ex. weight, speed
Independent Variable
The intervention, or what is being manipulated
Dependent Variable
The outcome of interest, which should change in response to some intervention
Central Tendency
- single value that is considered “typical” of the set of data as a whole
- ex. mean, median, mode
What kind of variables can you use for the mean?
- interval
- ratio
What kind of variables can you use for the median?
- ordinal
- interval
- ratio
What kind of variables can you use for the mode?
- nominal
- ordinal
- interval
- ratio
What are the measures of dispersion?
- Range
- Interquartile Range
- Variance
- Standard Deviation
Interquartile Range (IQR)
Reflects the variability of the middle 50% of the observations
Variance
- Measures the dispersion relative to the scatter of the values about their mean
- When values lie close to their mean, the dispersion is less than when they are scattered over a wide range
Standard Deviation
square root of the variance
Skewness
- One “tail” of distribution is longer than the other
- Negative & positive
Negative skewness
Longer tail is pointing toward the negative numbers
Positive skewness
Longer tail is pointing toward the positive numbers
