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Math Help - Statistics: Why are my frequencies wrong?

  1. #1
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    Joined
    Jan 2009
    Posts
    1

    Question Statistics: Why are my frequencies wrong?

    Hello all, forgive me if I do sometihng wrong when posting this, I am new here.

    Maybe someone can explain this better to me. My calculations are not coming out right. I need to create a frequency histogram and relative frequency histogram, however before I can construct those graphs I need to get my class frequencies right. For some reason, my answers keep coming out wrong. I asked my instructor about it and he also told me that I am wrong and the book is right, but he didn't elaborate (online class).

    Here are the math exercise from my book:

    In Exercises 3 and 4, use the following data set.The data represent the actual liquid
    volume (in ounces) in 24 twelve-ounce cans.


    11.95 11.91 11.86 11.94 12.00 11.93 12.00 11.94
    12.10 11.95 11.99 11.94 11.89 12.01 11.99 11.94
    11.92 11.98 11.88 11.94 11.98 11.92 11.95 11.93

    3. Make a frequency histogram using seven classes.
    4. Make a relative frequency histogram of the data set using seven classes.

    ----------------------------------
    I determined that the class range was .04. (Since the upper limit is 12.10 and the lower limit is 11.86. So 12.10 - 11.86 = .24 and 24/7 = .034 but you round up to .04)

    Now when creating my classes I got the following (Sorry about the underscore, it was the only way I could space them out):

    Class__________MyFrequencies______Book's Answer
    ---------------------------------------------------
    11.86 - 11.89_________3_______________2
    11.90 - 11.93_________5_______________4
    11.94 - 11.97_________8______________10
    11.98 - 12.01_________7_______________6
    12.02 - 12.05_________0_______________1
    12.06 - 12.09_________0_______________0
    12.10 - 12.14_________1_______________1

    So here's my problem, the Book reads the frequencies totally different. Why?

    According to the data set, the book says the first class' frequency is 2. But that doesn't make sense because there are three items that can be included in that class:
    11.86
    11.88
    11.89

    So, can someone please explain to me what it is that I am doing wrong. I just don't understand why 3 is not correct.
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  2. #2
    Member
    Joined
    May 2006
    Posts
    244
    Quote Originally Posted by LoveMyAJ View Post
    Hello all, forgive me if I do sometihng wrong when posting this, I am new here.

    Maybe someone can explain this better to me. My calculations are not coming out right. I need to create a frequency histogram and relative frequency histogram, however before I can construct those graphs I need to get my class frequencies right. For some reason, my answers keep coming out wrong. I asked my instructor about it and he also told me that I am wrong and the book is right, but he didn't elaborate (online class).

    Here are the math exercise from my book:

    In Exercises 3 and 4, use the following data set.The data represent the actual liquid
    volume (in ounces) in 24 twelve-ounce cans.


    11.95 11.91 11.86 11.94 12.00 11.93 12.00 11.94
    12.10 11.95 11.99 11.94 11.89 12.01 11.99 11.94
    11.92 11.98 11.88 11.94 11.98 11.92 11.95 11.93

    3. Make a frequency histogram using seven classes.
    4. Make a relative frequency histogram of the data set using seven classes.

    ----------------------------------
    I determined that the class range was .04. (Since the upper limit is 12.10 and the lower limit is 11.86. So 12.10 - 11.86 = .24 and 24/7 = .034 but you round up to .04)

    Now when creating my classes I got the following (Sorry about the underscore, it was the only way I could space them out):

    Class__________MyFrequencies______Book's Answer
    ---------------------------------------------------
    11.86 - 11.89_________3_______________2
    11.90 - 11.93_________5_______________4
    11.94 - 11.97_________8______________10
    11.98 - 12.01_________7_______________6
    12.02 - 12.05_________0_______________1
    12.06 - 12.09_________0_______________0
    12.10 - 12.14_________1_______________1

    So here's my problem, the Book reads the frequencies totally different. Why?

    According to the data set, the book says the first class' frequency is 2. But that doesn't make sense because there are three items that can be included in that class:
    11.86
    11.88
    11.89

    So, can someone please explain to me what it is that I am doing wrong. I just don't understand why 3 is not correct.
    Check that the book is using the same intervals as you are.

    .
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