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  1. R

    Calculate required sample size

    Thanks! These are really helpful. One more question... is there a version of the calculation I can carry out without estimating the standard deviation? It's hard to know what that would be in advance, and can very quite widely depending on the house types measured. If that's not possible...
  2. R

    Calculate required sample size

    Thanks! So one would choose a power level they were confident in, as they would a confidence level. Having done so, how would I use the known uncertainty level of my measurement method to calculate suitable sample sizes to measure different sizes of difference between pre- and post-refurbishment...
  3. R

    Calculate required sample size

    Thanks! Sorry to be dumb, but I'm not 100% sure what's meant by power in this context... would it be suitable to say I was looking for a 95% confidence level? For the statistical method I'd appreciate some guidance, my ill-informed Googling suggests that something like a paired samples t-test...
  4. R

    Calculate required sample size

    Hello, I have a test for the thermal performance of a building with a defined uncertainty margin (15%). I want to use it to measure the effects of refurbishments designed to improve thermal performance, but the effect of the refurbishments can be quite small (5-50%). In order to have confidence...