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    Building a Frequency Distribution in Excel

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    Please help with the following statistics problems.

    For the following data:

    15 25 13 10 9 17 13 15 20 5

    1) Calculate the mean and standard deviation
    2) Decide if it's a normal distribution
    3) Build a frequency distribution

    © BrainMass Inc. brainmass.com December 24, 2021, 10:52 pm ad1c9bdddf

    SOLUTION This solution is FREE courtesy of BrainMass!

    Dear Student:

    First input your data into an Excel spreadsheet (see the attached spreadsheet). Arranged the data in a column, each piece of data in its own cell. For calculating the standard deviation, go to an empty cell, click fx, a box opens where you can search for the function you are looking for. Type 'standard deviation' in the box, click Go and in the lower box you see alternative functions to use. Choose STDEV (this is the one you will most often use for standard deviation) and another box opens. Now, in this particular example, for number1 space, you input cell references B3:B12 where your data is located and click ok, and the result s = 5.69 appears in the cell. All other excel functions work in the same way. You can usually calculate the mean and standard deviation using the Excel functions (=AVERAGE) and (=STDEV). If you calculate them manually using the formulas, the answers will be exactly the same.

    Mean = 14.2
    Standard Deviation = 5.69

    This information alone does not give you information whether the distribution is normal or not. You may calculate the skewness of the distribution using the Excel function (=SKEW) = 0.36. This value tells you that the distribution is positively skewed to the right.

    Building a frequency distribution requires you to divide the data into classes and then count the number of data in each class. First check the range of you data; the minimum value is 5 and the maximum value is 25; thus the range is 25-5 = 20. It looks like it is best prepare four classes (the number of classes needed is not always exact science), each of which has a range of five. Our classes come out as follows: Class 5-10, Class 11-15, Class 16-20, and Class 21-25. Now we assign our data to the class in which they belong and then we count the frequency of data in each class.

    Class | Frequency
    5-10 | 3
    11-15 | 4
    16-20 | 2
    21-25 | 1
    Total | 10

    The Excel spreadsheet shows this frequency distribution in graphic form. The graph also illustrates that the distribution is close-by a normal distribution, although there is that little skewness on the right-hand side.

    Any basic statistics book includes a presentation of frequency distributions, e.g. Douglas A. Lind, William G. Marchal, & Robert D. Mason. (2002). Statistical Techniques in Business & Economics. 11th ed. Boston: McGraw-Hill.

    Good Luck!

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 10:52 pm ad1c9bdddf>