Standard Deviation
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Hi, I have S=[2 4 4 4 5 5 7 9]; can any one tell me how can I count and plot standard deviation in this values?
2 个评论
Image Analyst
2011-9-28
Sorry, no. Not until you supply more info on what you mean, like why you expect more than one standard deviation from that set of observations.
Firoz Alam
2011-9-29
采纳的回答
Walter Roberson
2011-9-29
numdev = floor((mean(S)-min(S))./std(S));
Determining the position of each standard deviation and plotting is left as a homework exercise.
Though possibly you want
numdev = floor((mean(S,2)-min(S,[],2))./std(S,[],2));
4 个评论
Firoz Alam
2011-9-29
Walter Roberson
2011-9-29
The one number it generates is the number of standard deviations that "fit" in to the actual range of the data. There are always an equal number of standard deviations around the mean value. If S is one standard deviation,
mean - 3 * S, mean - 2 * S, mean - S, mean, mean + S, mean + 2 * S, mean + 3 * S
or as appropriate: the above would be for numdev of 3.
Firoz Alam
2011-9-30
Shivakumar
2013-9-25
Thank you. I was helped by the answer.
更多回答（1 个）
the cyclist
2011-9-29
The standard deviation of the values in S can be calculated with the std() command:
>> std(S)
I'm not sure what you mean by plotting that standard deviation.
3 个评论
Firoz Alam
2011-9-29
the cyclist
2011-9-29
Sorry, but I am very confused. The standard deviation is one number. What exactly do you want to plot? What are you trying to do, see, or understand about that set of numbers by plotting? Type "help plot" for help on one simple plotting command.
Firoz Alam
2011-9-30
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2011-9-28
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