Posted: 1/30/2012 5:49:17 PM EDT
So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all  . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. |
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Haven't you already posted that pic a couple of times??? 
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Haven't you already posted that pic a couple of times??? Yes. It satisfies the requirement but doesn't show her face 
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So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 N +1 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. |
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He got it. It is always N+1 when determining Range.
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So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 N +1 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. |
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So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 N +1 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. That makes sense because there are 57 numbers from 54-110 (including 54). So work it with class width of 9 since that's the next integer after the decimal range value? Damn textbook mentions nothing about N+1, and of course the examples workout just fine without it. Thanks guys! |
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Nice Caboose
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Quoted: So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. Am I missing something here? Your class widths are 7, not 8. Shouldn't they be: 54 <= X <= 62 62 < X <= 70 70 < X <= 78 78 < X <= 86 86 < X <= 94 94 < X <= 102 102 < X <= 110 |
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Quoted: Quoted: He got it. It is always N+1 when determining Range.Quoted: So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 N +1 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. ETA: I'm fairly certain that my wife's text book indicated that the range is N + 1.
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So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 N +1 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. That makes sense because there are 57 numbers from 54-110 (including 54). So work it with class width of 9 since that's the next integer after the decimal range value? Damn textbook mentions nothing about N+1, and of course the examples workout just fine without it. Thanks guys! You can do it that way, though you will introduce a certain degree of skew into your data that way since your highest class will be 108 -> 116. You can use decimal widths if that's allowed (i.e. width 8.14) or you can pad the highest class to be 102 -> 110; according to my notes from Engineering Prob&Stats, classes are ALMOST always equal in length but do not necessarily have to be. |
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So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. Am I missing something here? Your class widths are 7, not 8. Shouldn't they be: 54 <= X <= 62 62 < X <= 70 70 < X <= 78 78 < X <= 86 86 < X <= 94 94 < X <= 102 102 < X <= 110 No, it's left end inclusive. Counting the numbers from 54 to 61 gives eight numbers - 54, 55, 56, 57, 58, 59, 60, 61. |
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So, I'm trying to help my girlfriend with her online statistics class. I have an engineering degree, so it should be easy peasy right? Well it mostly is, but this homework problem has me all . I'm sure I'm missing something easy, and I'm just not spotting it.
The problem is to create a grouped frequency distribution chart for a list of numbers with 7 classes. The numbers are: 88 88 110 88 80 69 102 78 70 55 79 85 80 100 60 90 77 55 75 55 54 60 75 64 105 56 71 70 65 72 Highest number: 110 Lowest number: 54 Range = highest -lowest = 110 - 54 = 56 N +1 Width = (range/number of classes) = 56/7 = 8 So starting with the lowest number and added the class width, I get these classes: 54 -> 61 62 -> 69 70 -> 77 78 -> 85 86 -> 93 94 -> 101 102 -> 109 That doesn't work since the highest number (110) doesn't fall into the limits of the highest class. When I change the class width to 9 it works, but that doesn't follow the textbook's method. It's just my way of fudging it to make the chart work. Am I missing something simple here? Thanks. I think he's got it. If you have two data items, 1 and 2, you need to add +1 to the higher value or else you will not include both of the values. 2-1=1. 3-1=2. You have two values, not one. |
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