Construct a frequency table and the Bar Chart frequency table Ms Lubna Ineirat

Construct a frequency table and the bar chart

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Construct a frequency table and the Bar- Chart. frequency table Ms. Lubna Ineirat # of decayed teeth Frequency(f) Relative frequency(r.f) Cumulative frequency(c.f) total 32
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Bar- chart Ms. Lubna Ineirat 33
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Example: the following are ages of 25 college students 19, 18, 22, 20,20, 21, 23, 20,19, 22,20, 21, 20, 19,19, 21, 19, 20, 18, 20, 22, 19, 20, 21, 20 Construct the frequency table and bar- chart. frequency table Ms. Lubna Ineirat Ages Frequency Relative frequency Cumulative frequency total 34
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Bar- chart Ms. Lubna Ineirat 35
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The frequency distribution and graphic presentation Frequency distribution: is a grouping of data into mutually exclusion categories showing the no of observations in each class. Class : is an interval being with lower bound(L)and with upper bound (U). Class Mid- Point(M.P): Is a point divides a class into two equal part C: (L, U) M.P= ( L+M) / 2 ex : C : (1, 5) M.P= Class frequency (F): The no. of observations in each class Length of class(width): obtained by subtract the lower limit of class from the next lower class (the width classes is equal) Relative frequency (r.f) = frequency /n Cumulative frequency: it can be computed by adding successive frequencies Cumulative relative frequency : it can be computed by adding successive relative frequency Ms. Lubna Ineirat 36
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Example: the grades of 30 students Frequency table Ms. Lubna Ineirat Classes Frequency Mid- Points (M.P) Relative frequency (r.f) Cumulative frequency (c.f) Cumulative relative frequency (c.r.f) 1 - 5 6 6 - 10 9 11 - 15 - 20 3 Total 37
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We can represent the above simple frequency table using the bar chart Ms. Lubna Ineirat classes frequency Class Boundaries 1 - 5 6 6 - 10 9 11 - 15 12 16 - 20 3 Total 30 38
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Class frequency table For large sample, we cant use the simple frequency table to represent the data We need to divide the data into groups or intervals or classes So , we need to determine: 1 . The number of intervals (K) Too few intervals , are not good , too many, are not because information will be lost. helpful to summarize the data. The formula to calculate K is K=1+3.22 log(n) Ms. Lubna Ineirat A commonly followed rule is that 6 K 15 39
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2. The Range (R) It is the difference between the largest and the smallest observation in the data set. 3. The width of the intervals (W) Class intervals should be of the same width Example: Assume that the number of observation equal 100 and the smallest value =5, and the largest value= 61 Then K=…… R=….. W=…… Ms. Lubna Ineirat R Range W K #ofclasses 40
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Histogram or Bar- chart Freq- polygon Ms. Lubna Ineirat 41
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Example: the following data are the grades of 40 students in a certain exam. Construct a freq-table and the bar chart. 94, 82, 77, 75, 70, 62, 89, 57, 35, 92, 80, 85, 55, 45, 69, 75, 72, 90, 82, 62, 50, 44, 67, 53, 82, 90, 91, 82, 78, 62, 59, 81, 81, 55, 70, 80, 57, 47, 82, 70. 1. Say the number of classes = 5 (given ) 2. Range = R = max-min= 3. Class width =W Class frequency table Ms. Lubna Ineirat Class limits frequency Class marks Class boundaries Total 42
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Example: a large internet retailer that sells medicine to pharmacies, is studying the lead time ( elapsed time between when an order is placed and when it is filled) for a sample of recent orders. The lead times are reported in days.
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