How to test if two means are significantly similar? I'm trying to run an experiment to see if my test and control (in this case 2 survey types) are similar, as opposed to significantly different, from each other.
Is there a test/way to do this? almost like an inverse of a t-test?

If this is the case, then I encourage you to determine the confidence interval of the mean difference (the narrower, the better) which will make your demonstration even stronger.
First, I would encourage you to visualize your sample data to check whether your assumption is likely or not. Then, one possibility could be to identify a 95% confidence interval (CI) for the difference of means (or even a 99% if you are sure that they are similar) , you can refer to the "basic steps" chapter of https://en.wikipedia.org/wiki/Confidence_interval. To demonstrate your point, your CI must include 0 and the lower and upper values of your CI must be very close to 0 (this depends of the unit/scale of your test of course).
I hope it helps!
