Exam One - measurement scales and descriptive stats Flashcards
measurement
a systematic process for assigning numbers to objects in such a way as to represent quantities of attributes
discrete data
each item is a separate, whole unit
continuous data
data for points along a scale that, at least theoretically, could be subdivided
What are the 4 scales of measurement?
1 - nominal
2 - ordinal
3 - interval
4 - ratio
nominal scale of measurement
numbers are category labels only
mutually exclusive
have none of the properties of a real number system
ordinal scale of measurement
categories can be rank ordered
- often have a great or less than relationship
- do not have the properties of distance and origin
interval scale of measurement
terms in question can be rank ordered and have equal intervals separate them
- lack property of origin
ratio scale of measurement
possess all three components of a real number system
What are the properties of a real-number system
1 - order:high numbers = increased quantities of the characteristic
2 - distance: magnitude of differences between umbers of categories is equal
3 - origin: measurement has a true zero point which represents absence of the measured property
descriptive stats
- relavent to all data types
- organize and summarize data to facilitate understanding
inferential stats
=estimates pop characteristics using sample data
- tests for effects (hypothesis testing and relationships)
What are 3 terms used in descriptive stats
1 - frequency
2 - central tendency (mean, median, mode)
3 - variability (range, SD)
If a sample resembles a normal distribution, _____% of observations are within 1 SD and ___% are within 1.96 SDs
68, 95
repeated samples of the same pop are (same/different) each time?
different