# Calculate the error given a tolerance

I have a noob statistics question.

Is there a function, such that given the residuals from the line of best fit, and a probability, A, it will return B such that there is an A probability of being within a radius B units from the line of best fit? Can standard deviation be used in this case?

For example: I have a set of data predicting how much a rubber band will stretch. I can very the length (independent variable) and measure how far it stretches (dependent variable). I have a linear regression using google spreadsheets functions (something like this). I want to be able to say that there is a 95% chance my rubber band will be within 5 centimeters from the predicted value.

I have done outside research, but it seems that more of statistics is concerned with proving two variables are related, instead of calculating the error given a tolerance probability.

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One student at my highschool suggested I calculate the standard deviation, using the the predicted value as the mean (calculating the square-root of the sum of the squares of the residuals). – Sam Nov 23 '13 at 0:00