Although this is not about CL or the activity builder, it is a pretty simple bug or I’m just not using the function properly.
desmos, fix your graphing calculator quickly (especially the “Inferences”)!
If you want the general idea, there is a Desmos Inference function called estimate that should do something (I’ve never learned statistics or distribution, so I was fooling around with the functions). When I typed estimate(1), I got Function "estimate" cannot be applied to a number. But when I tried the example code from the other error (estimate(x)) I got the same error!