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# how to construct frequency polygon

Question:Miles Number of Commuters Class Frequency 0 - 244 25 - 49 10 50 - 74 11 75 - 995 100 1241

Answers:Hi, 0-24........|XXXX 25-49......|XXXXXXXXXX 50-74......|XXXXXXXXXXX 75-99......|XXXXX 100-124..|X 11.............o 10......o ..9 ..8 ..7 ..6 ..5..................o ..4.o ..3 ..2 ..1__________o_____________ ......1...2...3...4...5 <== Categories Connect dots above for a frequency polygon. 0-24........ category 1 25-49...... category 2 50-74...... category 3 75-99...... category 4 100-124. category 5 I hope that helps!! :-)

Question:& cumulative relative frequency distribution showing "greather than or within" relative frequencies, in excel. oops I made a typo, I meant to say "greater than."

Answers:I will give you an example, by using the prime numbers up to 50. They are 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47. We begin by dividing into appropriate intervals, usually of the same length. We will divide into five equal intervals, The choice of how many intervals to use is purely stylistic. We make a rectangular chart. Down the left side, we list our intervals. Across the top, we list headings for columns that are, in order, frequency (how many in the interval), relative frequency, and cumulative frequency: Interval Freq. Rel. Freq. Cumul. Freq. 1-10.........4......4/15.=78.7 %. 4 11-20.......4......4/15=78.7%.. 8 21-30.......2......2/15=39.3%.. 10 31-40.......2......2/15=39.3%. 12 41-50.......3......3/15=20.0%. 15 Total.......15... ..1 = 100.0%. 15 To explain, we begin with frequency. There are 4 primes between 11 and 20, for example, so the frequency is 4. There are 15 primes in our whole sample, so the relative frequency for the intereval 11-20 is 4/15, or frequency divided by total. The cumulative frequency is the SUM of the frequencies up to here, or 4 + 4 = 8 (the first 4 is for the interval 1-10, and the second 4 is for the interval 11-20). Cumulative frequency, thus, is like keeping a running total. To check it, for the last interval in your table, it will always be the total number of data points in your sample. There are two ways to do this in excel. One is to compute it by hand as I have shown above, and then just enter these data in a spreadsheet. Then, use the usual commands for making pie charts and histograms. The second is to enter the data for frequency, and label your intervals. Then, you can insert the next two columns, with the insert column command. By using arrays, you can call a(n) the nth entry in the first column, and in this example, set b(n)=a(n)/15 for all n (I cannot remember the exact excel command here, but it is a lot like this). For the third column, you would put the first entry in (call it c(1), and then let c(n+1)=c(n)+a(n+1) for the rest of your table. That will give cumulative frequency. The commands are slightly dependent on your system and on how you begin, but this is the key idea.

Question:I have no idea how to do this please help me!! Construct a frequency distribution table using the cotton futures price data. Use the categories 30.00-39.99; 40.00-49.99; 50.00-59.99; 60.00-69.99; 70.00-79.99; 80.00-89.99 (price in cents/lb) Include in your frequency distribution table columns for lower limit, upper limit, class midpoint, frequency and cumulative frequency. Please, any suggestions or help would be great. I know your supposed to use Excel but I don't know how to actually do it. Here's the cotton futures price data: http://www.aaec.ttu.edu/faculty/eelam/3401/ClassNotes.htm