To calculate the standard deviation for a set of percentage changes, you can use the following formula:

σ = sqrt [ Σ (X - M)^2 / N ]

Where: σ = standard deviation Σ = sum of X = each value of percentage change M = the mean of the percentage changes N = the total number of values

Here's how you can calculate the standard deviation for a set of percentage changes:

(10% - 5% + 15% - 7% + 8%) / 5 = 4.2%

10% - 4.2% = 5.8% -5% - 4.2% = -9.2% 15% - 4.2% = 10.8% -7% - 4.2% = -11.2% 8% - 4.2% = 3.8%

5.8%^2 = 33.64% (-9.2%)^2 = 84.64% 10.8%^2 = 116.64% (-11.2%)^2 = 125.44% 3.8%^2 = 14.44%

33.64% + 84.64% + 116.64% + 125.44% + 14.44% = 374.76%

sqrt (374.76% / 5) = 7.71%

Therefore, the standard deviation of the percentage changes is 7.71%.

To calculate the standard deviation for percentage change, you can follow these steps:

Here is the formula for standard deviation of percentage change:

σ = √[ Σ( Xi - X )^2 / N ]

where:

• σ is the standard deviation
• Σ is the sum of
• Xi is the percentage change for each observation
• X is the mean percentage change
• N is the number of observations

Note: If you're calculating the percentage change between two values, you can use the formula:

Percentage change = (new value - old value) / old value * 100

And then apply the above formula for calculating standard deviation of percentage change.

And what if I only have the „mean“ data and no standard deviation (for example: mean OS = 36.7 months)? Is it possible to work with only this data?