Q&A for How to Calculate Mean Deviation About Mean (for Ungrouped Data)

Add them together to get a mean of 14. Subtract each number minus 14 and find the absolute value of those differences: 10, 6, 9, 2, 9, 31, 6, 7. Find the mean of those deviations by dividing by 8.

Find the mean: (7+6+3+4+10)/5 = 6. Find the absolute difference of each number from the mean. These are 1, 0, 3, 2, 4. Find the mean of these differences: (1+0+3+2+4)/5 = 2.

Find the mean: (1+3+7+9+10+12)/6=42/6=7 Find the deviation from the mean of each data point by subtracting each value minus the mean: -6, -4, 0, 2, 3, 5 Take the absolute values: 6, 4, 0, 2, 3, 5 Find the mean of the deviations: (6+4+0+2+3+5)/6=20/6=3.33.

To find mean deviation, you must first find the mean of the set of data. Next, you find the distance between the mean and each number. For example, if the mean is 5, and a number is 7.6, the distance is 2.6. Note that there will be no negative distances, as stated in the rule of absolute value. Then, find the mean of those distances, and you have your mean deviation.

Standard deviation is similar to the mean deviation, but you cannot treat them as equals. The standard deviation uses the deviation values as in this article, but then squares them, finds the average, and then the square root of that value. For more on standard deviation, see the wikiHow article How to Calculate Standard Deviation .

If you have a set A={a,b,c,d...} and a corresponding set of probabilities B= {e,f,g,h...} then the standard deviation is the probabilities multiplied together.

"Group data" means that instead of having individual values in your data set, you have groups and frequencies. For example, you may know that there are 8 scores from 1-10, 7 scores from 11-20, and 6 scores from 21-30. To find the mean of grouped data like this, use the central value of each group - in this case, 5, 15, and 25. Multiply those central values by the frequency of data in the group. So, find 5*8 =40 for the first group, 15*7=105 for the second group, and 25*6=150 for the third group. Add these values, 40+105+150=295, and divide by the total number of data points (21) to find the mean. Thus, 295/21=14.0 is the mean of this grouped data.

This is clever, because you are given variables instead of values. The work, however, is the same, but you have to work with symbols instead of numbers. You have 4 terms, a, a+b, a+2b and a+2b (I assume you copied this last one incorrectly, since a+2nb doesn't make sense). The mean of these terms is (a+(a+b)+(a+2b)+(a+2b))/4 = (4a+5b)/4=a+1.25b. The differences of each term from the mean are: 1.25b, .25b, .75b, .75b. The mean of these four differences is (1.25b+.25b+.75b+.75b)/4=3b/4=0.75b.

You can't, without more information. The formula is Dev=Sum(x-mean)/N. You can rearrange this a bit to get N*Dev.=Sum(x-mean).To go any further, you need to be told the values themselves.

First you have to find the sum of the given data and then divide the sum by 7 (7 is how many numbers are given in the data). By dividing you get 9.57.

First find the mean, which is 9.57. Then mean deviation is x-the mean after removing the negative signs. Then you arrive at dividing by the value. Finally, you get 3 as mean deviation.

The mean of the eight numbers is 13.0875. Find the absolute value of each number minus 13.0875. Then add those values together and divide by 8 to get the mean deviation of 1.34.