Lecture 1-4 Flashcards
What do you have be to double-check when reading values in histogram and bar graphs(clustered, stacked, etc)?
If the values are row, column totals, or sample totals(n)
What are charts that display bivariate relationships?
Panelled pie charts, panelled histograms, stacked/ clustered bar graphs,
What characteristics do descriptive data focus on?
Centre pf data-main
Spread of data-average
Shape of data-ratio level variables only
What characteristics do descriptive data focus on?
Centre pf data-median
Spread of data- mean average
Shape of data-ratio level variables only
What does descriptive stats depend on?
Level of measurement for variables
Descriptive stats- define and describe the difference between mode, median and mean
Mode: most common.
Median: the middle of the data. “50th percentile”
Mean: average of data.
Which level of measurement is used for which description, and why?
4 leavels of measurement from least to most accurate:
Dictonomous: Mode
Nominal: Mode
Ordinal: Mode, Median
Ratio: Mode, Median, Mean
Ordinal variables: can’t do Mean because can’t apply mathmatical formula
Ratio: can do Mean beacuse can do math formula: total of values/ total of sample
What does cell frequency mean?
“Hard counts” of a cell
What does IAP mean?
Not applicable
In frequency percentage, What is the difference between percent vs. valid percent vs. culumulative?
Valid percent excludes missing data.
Culumulative percent: culumulating previous valid percent and helps to find Median of data
What is the equation for mean? What does each of the symbol mean?
Mean= Sigma X/ n
How to find median in ordinal variables?
By stacking values in hierachy. culumulative percent. Cannot locate the exact value, but only rough
What does measures of variation tell us about data? How is it different from central tendencies?
Measures of variation tell us - how spread out the data is. It is important because
What is a range?
Range: difference b/w max and min
What is the Inter-Quartile Range and why is it important?
-Distance between the 25th and 75th percentile, excluding the top and bottom 25 percentile
-Important because it is an effective way to avoid calculating “outliers” if there are a lot present