# Calculate Confidence Interval for Binary Data Set

#### davidb88

##### Board Regular
Hi -

I have a data set that is organized by date in column A and then in column B it is binary data of 0's and 1's where 1 means the customer was declined and 0 means it was not. Each week I calculate the rate that customers were declined and plot that out over a 12 week period. I now would like to incorporate confidence intervals into the report, so that if there is movement in the overall decline rate outside of the confidence interval I know it is something worth looking into.

Is there any way to do this with binary data? I know there is a CONFIDENCE function built into Excel (https://support.office.com/en-us/article/CONFIDENCE-function-75ccc007-f77c-4343-bc14-673642091ad6), however, the problem then becomes not knowing how to calculate the standard deviation of the data set because it is made up of just 0's and 1's.

### Excel Facts

Test for Multiple Conditions in IF?
Use AND(test, test, test, test) or OR(test, test, test, ...) as the logical_test argument of IF.

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