Exam 1 - Study Guide Flashcards
Element
o The entities on which data are collect
o Ex. The restaurant
Variable
o A characteristic of interest for the elements
o Ex. Sandwiches, salads, soups, etc.
Observation
o The set of measurements obtained for a particular element
o Ex. Burger King: chicken sandwich, side salad, potato soup (1 observation)
Categorical Data
Data that can be grouped by specific categories
Use either the nominal or ordinal scale of measurement
Quantitative Data
Data that use numeric values to indicate how much or how many
Use either the interval or ratio scale of measurement
Nominal
Labels or names that are used to identify an attribute of the element
Ex. Ford Motor Company, US, Purple
Ordinal
Exhibit the property of nominal data but ranking is meaningful
Ex. AAA, AA, A, BBB, BB, B, CCC, CC, C, etc.
Interval
If the data have all the properties of ordinal data and the interval between values is expressed in terms of a fixed unit of measure
Always numeric
Ex. SAT scores
Ratio
The data have all of the properties of interval data and the ratio of the two values is meaningful
Requires that a zero value be included to show that nothing exists for the variable at that point
Ex. Distance, height, weight, time
Sample
the smaller group of elements in a particular study; a subset of the population
Population
the larger group of elements in a particular study; all of the elements in a particular study
Data Size
The number of individual organisms in a sample
Population Size
The number of individual organisms in a population
Sample “Statistic”
Any quantity that you derive from a sample taken from a population with the intention of using this quantity to estimate same but unknown parts of the population
Population “Parameter”
A numeric value that represents the population
Dot Plot
A statistical chart consisting of data points plotted on a fairly simple scaled
Histogram
An accurate representation of the distribution of numerical data
Stem-and-Leaf Display
A graphical display used to show simultaneously the rank order and shape of a distribution of data
Ogive
A cumulative frequency graph
Pie Chart
Provides another graphical display for presenting relative frequency and percent frequency distributions for categorical data
Cross Tabulation
A tabular summary of data for two variables
Pivot Table
Can be used to summarize the data for two or more variables simultaneously
Scatter Diagram/Trendline
Scatter Diagram: a graphical display of the relationship between two quantitative variables
Trendline: a line that provides an approximation of the relationship
Bar Chart
A diagram in which the numerical values of variables are represented by the height or length of lines or rectangles of equal width
Mean
o Average value o The most important measure of location o The central location of data o Sample = bar over x o Population = Greek letter u o Excel: =AVERAGE(a1:12)
Median
o The value in the middle when the data are arranged in ascending order
o Excel:=MEDIAN(a1:a12)
Mode
o The value that occurs with greatest frequency
o Excel: =MODE.SNGL(a1:a12)
o Excel: = MODE.MULT(a1:a12) (Fancy Formula)
Quartiles 1, 2, and 3
o Dividing a data set into four parts with each part containing approximately 25% of the observations
o 1st is 25%, 2nd is 50%, 3rd is 75%
o Excel: =QUARTILE.EXC(a1:a21,1)
Percentiles
o Provides information about how the data are spread over the interval from the largest value to the smallest value
o Excel: =PERCENTILE.EXC(a1:a21)
Range
o The simplest measure of variability
o Largest value – smallest value
Interquartile Range
o A measure of variability that overcomes dependency on extreme values
o Q3 – Q1
Varience
o A measure of variability that utilizes all the data
o The difference between the value of each observation and the mean
o Excel: VAR.S(a1:a21)
Standard Deviation
o The positive square root of the variance
o Excel: STDEV.S(a1:a21)
Coefficient of Variation
o How large the standard deviation is relative to the mean
o Usually expressed as a percentage
o Excel: (standard deviation/mean x 100)%
