Unformatted text preview: "Dot glot
.. ’ Dot plots are constructed by 0 Drawing a horizontal line labeled with the variable name
0 Marking regular values of the variable on it
o Placing a dot for each observation above the corresponding value Ex 13: The following set of data is the scores obtained for midterm test on a 0100 scale. Construct a dot plot.
10, 90, 95, 100, 65, 50, 60, 50, 90, 55, 60, 70 o o e
. o a o a o o o o 0 10 20 30 $0 50 60 70 30 90 100 ~ m! 45 Can identify unusual data (outliers)
. Can identify concentrated points since the number of dots represent the frequency of occurrence of that value #6 §temangLgaf plot 0 Each observation is represented by a stem and a leaf. Usually the stem consists of all the digits except for the ﬁnal one, which is the leaf.
0 Place the stems in the left hand side starting from the smallest 0 List the leaves on the right in increasing order {50 Ex 14: Math 1320 midterm exam scores of 20 students are given below. Create a stem—andleaf plot for these scores. 80 85 75 90 62 50 55 65 75 82 70 25 92 57 63 72 81 95 41 69 2
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9 7K Histogram
A histogram is a graph that uses bars to portray the frequencies or the relative frequencies of the possible outcomes for a quantitative variable.
Steps 0 Divide the range of the data into intervals of equal width. (For discrete variables with few values, use the actual possible values.
Count the number of observations (the frequency) in each interval, forming a frequency table. 0n the horizontal axis, label the values or the endpoints of the intervals. Draw a bar over each value or interval
with height equal to its frequency (or percentage). 0 O egg“.;=::;;,A... '=a==:i  , " r»:x;;vxaeaseasa;;¢‘;.........,1,',,,,?,
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