Search results

  1. Y

    Minimum Accepted Sample Size for Tolerance Interval (confidence interval)

    Maybe I get this wrong but the data look good to me if I type your values in the website tool that katxt proposed: https://statpages.info/tolintvl.html 7 samples are sufficient to be 90% sure that 95% of the hypothetic population fall between the upper (24) and lower (7.05) limits. This...
  2. Y

    Minimum Accepted Sample Size for Tolerance Interval (confidence interval)

    Hi, I am not an expert in Design Of Experiments but I don't think that there is a one-fits-all answer to the sample size. You need to have some estimations about your specimens before you can calculate a sample size: approximate mean value, approximate standard deviation, do you values roughly...
  3. Y

    How to calculate sample size to check if 95% of values are between predefined upper and lower limit

    @katxt: Fantastic! That's exactly what I was looking for. In case somebody else has the same question: You need to have an estimate for the mean µ and the standard deviation σ (either from a previous study or calculated on the basis of a preliminary test of maybe 10 to 20 apples. Ideally, your...
  4. Y

    How to calculate sample size to check if 95% of values are between predefined upper and lower limit

    @hlsmith Thanks for the tip with the publication. Did you mean 'Planning Study Size Based on Precision Rather Than Power' from Kenneth Rothman and Sanerc Greenland? Unfortunately, it is not open access. From what I can see in the abstract, they base their calculation on the Confidence Interval...
  5. Y

    How to calculate sample size to check if 95% of values are between predefined upper and lower limit

    Thanks for your replies. I agree that a rejected Kolmogorov-Smirnov will not solve my problem. I was wondering if I could proceed like this: 1. I assume that the acidity of apples is normally distributed. This way, 95% of my samples should lie between x̄ +/- 2*σ. 2. I measure the acidity of 10...
  6. Y

    How to calculate sample size to check if 95% of values are between predefined upper and lower limit

    Dear Forum, I am stuck on a sample size estimation question. I looked at the FAQs and the previous questions but I do not think the answers there apply to my scenario (correct me if I am mistaken). Imagine I want to produce apple pies. My pie only tastes good if the apples have an acid content...