Education Technology

Solution 28770: Correcting a Domain Error when Calculating a 1-Prop Z-Test on a TI Graphing Calculator. 

Why do I get a domain error when calculating 1-Prop Z-Test on TI graphing calculators?

When calculating a 1-Prop Z-Test with the number of successes provided as a percentage, the calculation will result in a domain error unless the success percentage is converted to a value.

Example: The hypothesized proportion is .9, with 80% successes, and a sample size of 200. For this example, p=.9, and n=200, but if x is entered as .8, as a partial success a domain error will occur.

1) x would be 80% of the sample size of 200
2) 200*.8=160
3) x=160.

The correct values would be entered as:


For more information please refer to your graphing calculator guidebook.

Last updated: 6/16/2023