You will need
- - discrete variational series.
- - the range;
Bring existing data into the form required for graphing. Divide the aggregate sample into two equal parts, to obtain a uniform position of the points on the graph. Most often, this is segmented into the time intervals: months, days, years. To use this method, calculate the characteristic value for each time period, for example, how many of units sold in each month. If the symptom varies slightly and discretely, use asinternal variational series (this can be, for example, student assessment).
Transmit the data to the table, you got two lines: first, specify the intervals or businterface values, and the second – the frequency of the common symptom. Add one more line – the accumulated frequency characteristic values. Complete this column, sequentially adding the frequencies from the second row. For example, if each month of the quarter consistently has sold 5, 3, 4 pieces of equipment, the accumulated frequency is equal to 5, 5+3, 5+3+4, that is, 5, 8, 12. Please note, each next value of the accumulated frequency will always be equal to or greater than the previous one, so the graph will never go down.
Build the coordinate system. On the horizontal axis place the characteristic values and on the y-axis is the cumulative frequency. Specify next to the axis name and unit of measure.
Dot in accordance with your table. To do this, use the values of the first and third rows, the row "frequency characteristic" to participate in building will not. Measure on the horizontal axis the value of the measured characteristic on the y-axis is the accumulated frequency, and at the intersection of the set point. When all the points are built, connect them with a polyline. This line is called cumulate number distribution.
To build cumulate in Excel, enter data in rows or columns, then click "insert" - "chart". Select one of the matching scatter plots, select the desired to build the data (don't forget, only two lines – the characteristic value and the cumulative frequency) and click "finish". If necessary, correct the finished graph by using the window settings.
Advice 2 : How to build interval series
When the number of distribution already given, you can immediately start his research. But in some problems the initial data is presented just numbers (weight, amount, quantity – any value of the parameter or attribute). In this case, in order to begin your analysis, first you need to build the interval number.
You will need
- the value of the parameter.
If the parameter values change over time, use as intervals time intervals, for example, hour, day, month, year. If you select minimum interval, consider the number and scatter of data, try to keep the number distribution was most informative and at the same time compact. For example, if you are given data by months for two years, split for years nothing will be able to speak, and use as a interval a month in some cases will lead to the erosion data. The optimal solution in this case will be broken down by quarters.
If time for sampling is not matter, form, interval intervals depending on the values. For this rate range, maximum and minimum value, and select the amount of space. You can use this method: subtract from the maximum value to the minimum and the difference, divide by the desired number of intervals. Then set boundaries, of course, better if it will be integers. For example, you are given 32, 33, 35, 38, 45, 47, 48, 50, 58, 59, 63. After settlement you will receive (63-32)/5=6,2. Round the interval size up to 7. Thus, you get the intervals: (32-39), (40-47), (48-55), (56-63).
Please note, it is best to make the boundaries of the intervals are not overlapping, i.e. the next interval does not begin with the same number, and more per unit. This will allow you to avoid disagreements and misunderstandings.
Once you distribute all the intervals, count the number of values in each of them. Record the results in a table where in one row it will show borders, the other with the number of values lying within the boundaries of this interval. In the above example, the calculation of the number of results will look like this: interval (32-39) includes the values 32, 33, 35, 38 – only 4 values. So, in the first table cell below this interval, enter the number 4. Similarly, calculate values for the following intervals: (40-47) – 2, (48-55) – 2, (56-63) – 3.