test #2-graphing and summarizing data Flashcards
what is a bar graph
-vertical/horizontal.
- for categorical data
-bars separated by space
what is a Pareto chart
- same as bar graph but in increasing or decreasing order.
a complete frequency distribution table contains;
values, frequency, relative frequency and cumulative frequency
what is relative frequency
1/19, 9/19, 4/19…
what is a grouped frequency distribution table
-organizes grouped data
-5 to 20 groups is ideal
-calculate class width for classes
difference between discrete or continuous data in a table
discrete; x-y
continuous; [x,y[
what is a histogram
-only for continuous data
- similar to a bar graph, but the bars are side by side.
-different bars are the different classes
what is a frequency polygon
only for grouped data
made by joining the mid values of the groups
what is a cumulative frequency polygon
only for grouped data
requires the upper bound of each class
how can you find the upper bound for discrete data.
x-y
UB: y.5
how can you find the upper bound for continuous data
[x,y[
UB: y
what is a stem and leaf plot
represents data by splitting each value into a stem (first digit) and leaf (las digit(s))
why do we use measures of central tendency
to identify what is normal for a data set
what is the mean
the average
it is very outlier sensitive.
what is the median
the middle value
values have to be placed in increasing or decreasing order
not outlier sensitive
what is the mode
the most frequent
how do you find the median and mode for groupe data
medial class and grouped data
what are measures of dispersion
it describes how spread out or dispersed the data is
what is the range
the difference between the lowest and the highest values. [min,max]
what is standard deviation
a useful measure of how much the data values deviate from the mean root variance
what is variance
the average of the square differences from the mean (standard deviation) exp2
when do you use sx vs ox for standard deviation
sx when the data set is less than 30 and ox when its greater than 30
what are measures of position
the location of data values relative to other values in the same data set
how can you find outliers
a value is < Q1-1.5(IQR)
a value is > Q3-1.5(IQR)
