The phrase "assumed standard deviation" is correct and usable in written English.
It can be used in statistical contexts where a standard deviation is estimated or presumed based on certain assumptions or prior knowledge.
Example: "In our analysis, we used an assumed standard deviation of 5 to calculate the confidence intervals."
Alternatives: "estimated standard deviation" or "presumed standard deviation".
The sample size used in this study was based on a priori knowledge on natural loss of older animals [29], [30], the expected loss being 20% and 50% in the mature and senescent age groups, respectively, and on the assumed standard deviation of ∼11% in the breaking load of rat femur, the primary outcome [31].
A power analysis was performed with the publicly available PS software [49], [50] to assess that the chosen sample size was sufficient to detect a 1.5-fold difference or greater in expression between the two patient groups with an assumed standard deviation of 0.6 and α<0.05 in a two-sided t-test.
The effect of varying the assumed standard deviation is also shown.
The assumed standard deviation was set to 20 points based on the results of other studies [ 117- 120].
The assumed standard deviation for A1C and the coefficient of variance for weight were 1.2 and 3%, respectively.
13 A 6 point difference in the PRWE equates to a standardised effect size of 0.3, for an assumed standard deviation (SD) of 20 points.
We assume standard deviation of 0.06 of the difference of two groups.
Recruitment of 60 participants to each trial (30 to each arm within each trial), assuming 20% loss to follow-up, provided 80% power to detect a 12.5 point difference in BSID-III score assuming standard deviation (SD) of 15 points.
For SF-36v2 physical and mental component summary scores, a sample of 238 completed participants has 90% power to detect a difference of 3.9 units (assuming standard deviation of 10 [ 19]).
For a two sided test at 80% power and alpha value of 0.05, the sample size required to detect a 4 mmHg difference in IOP (assuming standard deviation of 5 mmHg) is 25 per group.
Our sample size calculation showed that 156 participants were required to have 80% power to detect (at a 5% significance level) a mean score difference of 0.1 (assuming standard deviation = 2).
