The phrase "correct sample size" is correct and usable in written English.
It is typically used when discussing research or experiments that involve collecting data from a specific group or population. Example: "In order to ensure the accuracy of our results, we must make sure to use a correct sample size when conducting our study."
The correct sample size to use in an experiment depends primarily on three things: the design of the study, the size of the treatment effects that one reasonably expects or hopes will occur, and the acceptable level of risk that effects of that size will indeed occur but the statistical tests will fail to detect.
The rationale behind choosing a correct sample size is to weigh the benefits; one can gain in information against the cost of increasing the sample size.
In a clinical trial, the knowledge of instrument's responsiveness helps in the selection of measures, in setting the correct sample size and assists in prioritising the number of outcomes to be assessed.
In the process of preparing this material for inclusion in a doctoral thesis, the following minor errors were noted: ▸ Remien study (tables 1 and 2) – the correct sample size is 215; data were, however, entered correctly.
Although the authors performed their analyses according to the intention-to-treat principle on what they claim is the correct sample size, we worry about the fact that the attrition rate was 10% (4/40) in the placebo group, whereas only 2% (1/41) withdrew from Phytalgic®.
The present study aims to evaluate the feasibility of moxibustion as an adjuvant for conventional treatment in patients with BPH and to determine the correct sample size for verifying, in future studies, the effectiveness and safety of the integrative treatment compared with conventional treatment for patients with BPH accompanying LUTSs.
▸ Van Es study (table 2) – the correct sample sizes for the intervention and control group are 33 and 34 respectively; data were, however, entered correctly.
Since the exact number of source population of respondent is less than 10,000, we used correction formula of nf = ni / (1 + ni/N) where nf = corrected sample size ni = uncorrected sample size, and N = total number of all the source population [ 9].
Consequently, the corrected sample size became 183.
The corrected sample size was therefore: n´= n · ED = 346 · 1.5 = 517.
With an expected dropout rate of 20%, the corrected sample size for the CRCT is determined at 520.
