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Statistics Quiz 2
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Terms in this set (22)
classes
groups or categories of data
class width
the difference between two consecutive lower class limits in a frequency distribution (size of each class/group)
range of data
maximum value- minimum value
class width equation
range/# of classes rounded up to the next whole number
class limits
The end points of a class which specify exactly which values fit into the class.
frequency
tally expressed by numbers
midpoint
the point halfway between the endpoints of a class
midpoint equation
(beginning point+ end point)/2
relative frequency
a ratio that compares the frequency of each category to the total written as a decimal
relative frequency equation
class frequency/total frequencies from all classes
cumulative frequency
the sum of the frequencies for that class and all previous classes
class boundaries
the numbers that separate classes without forming gaps between them (0.5 above and 0.5 below the class limits)
frequency histogram
bar graph with bars touching that plots the frequency scores (midpoints) on the x-axis and the frequencies on the y-axis
frequency polygon
a line graph that plots the frequency scores (midpoints) on the x-axis and the frequencies on the y-axis and emphasizes the continuous change in frequencies (must be 'closed' with both ends of graph touching x=0)
relative frequency histogram
a histogram that plots the frequency scores (midpoints) on the x-axis whose vertical axis shows the percent of the data values in each interval
ogive
a line graph that represents the cumulative frequencies for the classes in a frequency distribution using class boundaries (first low, all rest upper) on x-axis with first point always starting at y=0
stem and leaf plot
data value is split into a "leaf" (usually the last digit) and a "stem" (the other digits) (if there is gap in stem numbers, fill them in with no leaves)
scatter plot
A graph with points plotted to show a possible relationship between two sets of data.
time series chart
a graph of a data set that is composed of quantitative entries taken at regular intervals
pie chart
a circular graph showing the relative frequency as a percentage of each category of qualitative data
Pareto chart
a bar graph for qualitative data where the height of each bar represents the frequency or relative frequency (%) and the bars are organized from most frequent to least frequent with a space between
ways to get class width
1. subtracting consecutive midpoints
2. subtracting consecutive lower limits
3. subtracting consecutive upper limits
4. formula= range/(# of classes) rounded to the next whole number
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