Medical statistics and Data Science: Clinical Trials

     

News:

A book “How to get started with Stata”, which is scheduled to be published in Amazon in the 28th February 2025

How to get started with Stata for beginners

Link to the book description

Sample size calculation and power analysis

You may watch a Youtube video so called "Biologist talks to statistician" (link)

One sample test for means

  1. Compute sample size

    2. Significance level (α):
    Desired power (1- β):
    Two-sided or one-sided test
    Expected mean of the sample:
    Expected standard deviation of the sample :
    Mean of the reference group:

  2. Compute power

    3. Significance level (α):
    Sample size:
    Two-sided or one-sided test
    Expected mean of the sample:
    Expected standard deviation for the sample :
    Mean of the reference group:

Paired test for means

  1. Compute sample size

    2. Significance level (α):
    Desired power (1- β):
    Two-sided or one-sided test
    Expected mean of the difference (after - before):
    Expected standard deviation of the difference :
    Null hypothesis for mean of the difference:

  2. Compute power

    3. Significance level (α):
    Sample size:
    Two-sided or one-sided test
    Expected mean of the difference (after - before):
    Expected standard deviation for the difference :
    Null hypothesis for mean of the difference:

Comparing two-sample means

  1. Compute sample size

    2. Significance level (α):
    Desired power (1- β):
    Two-sided or one-sided test
    Expected mean for the intervention group:
    Expected standard deviation of the mean for the intervention group :
    Expected mean for the control group:
    Expected standard deviation of the mean for the control group :

  2. Compute power

    3. Significance level (α):
    Sample size per group:
    Two-sided or one-sided test
    Expected mean of the intervention group:
    Expected standard deviation for the mean of the intervention group :
    Expected mean of the control group:
    Expected standard deviation for the mean of the control group :

Comparing two-sample proportions

  1. Compute sample size

    2. Significance level (α):
    Desired power (1- β):
    Two-sided or one-sided test
    Expected proportion for the intervention group:
    Expected proportion for the control group:

  2. Compute power

    3. Significance level (α):
    Sample size per group:
    Two-sided or one-sided test
    Expected proportion for the intervention group:
    Expected proportion for the control group:

Two-sample hazard ratio using the Cox proportional hazards model

  1. Compute sample size

    2. Significance level (α):
    Desired power (1- β):
    Two-sided or one-sided test
    Expected hazard ratio by comparing the intervention group to the control group:
    Expected failure proportion ("number of cases"/"total number of sample size" at the end of the follow-up :
    Expected proportion of withdraw from the study:

  2. Compute power

    3. Significance level (α):
    sample size per group:
    Two-sided or one-sided test
    Expected hazard ratio by comparing the intervention group to the control group:
    Expected failure proportion ("number of cases"/"total number of sample size" at the end of the follow-up :
    Expected proportion of withdraw from the study:

Prevalence Studies

  1. Compute sample size

    2. Significance level (α):
    Expected prevalence among the population:
    Maximum acceptable error for the expected prevalence

  2. Compute maximum error

    3. Significance level (α):
    Expected prevalence among the desired population:
    sample size: