help sampsi_fleming
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Title

      Exact sample size calculation for single-stage designs

Syntax

        sampsi_fleming [, options]

    options               Description
    -------------------------------------------------------------------------
    Main
      p0(#)                specifies the null proportion.
      p1(#)                specifies the alternative proportion.
      alpha(#)             specifies the type I error, the default is 0.05.
      power(#)             specifies the power, the default is 0.9.
      start(#)             specifies the start sample size in the initial
                            sample size search, the default is 1.
      end(#)               specifies the largest sample size in the initial
                            sample size search, the default is 40.
    -------------------------------------------------------------------------

Description

    A single stage design requires all n patients to receive and experimental
    treatment.  Within a specified time period they will be observed to have
    responded (success) or not (failure).  The probability of a success in
    the trial is p and this is compared to a fixed value p0, which is the
    probability of a success under the null hypothesis, this could represent
    no treatment or standard treatment.  The trial therefore tests the null
    hypothesis H0:p=p0 against the alternative hypothesis H1:p>p0.  A
    particular value p1 (p1>p0) is considered to be the desired probability
    of success.

    The number of successes, S, will follow a Binomial distribution with
    parameters n and p. A sample size is found by using a search such that
    P(S>=u|p0)<=alpha and P(S>=u|p1)>=power. The design is therefore
    characterised by the sample size n and the critical value u, the null
    hypothesis is rejected if there are u or more successes in a trial of
    size n.

Latest Version

    The latest version is always kept on the SSC website. To install the
    latest version click on the following link

    ssc install sampsi_fleming, replace.

Options

        +------+
    ----+ Main +-------------------------------------------------------------

    p0(#) specifies the null proportion.

    p1(#) specifies the alternative proportion.

    alpha(#) specifies the type I error, the default is 0.05.

    power(#) specifies the power, the default is 0.9.

    start(#) specifies the start sample size in the initialgrid search, the
        default is 1.

    end(#) specifies the largest sample size in the initial grid search, the
        default is 40.

 Examples


    The default sample size calculation

      sampsi_fleming

    The default design has a sample size of 47 and a critical value of 15,
    the type I error is 0.0366 and power is 0.9012.

      sampsi_fleming, p0(0.45) p1(0.5) s(800)

    A sample size of 861 and a critical value of 412 gives a type I error of
    0.0499 and a power of 0.9024.

      sampsi_fleming, a(0.01) p(0.8)

    A sample size of 52 and a critical value of 18 gives a type I error of
    0.0099 and a power of 0.8245.

      sampsi_fleming, p0(0.1) p1(0.35) a(0.01) p(0.8)

    A sample size of 25 and a critical value of 7 gives a type I error of
    0.0095 and a power of 0.8266.

Author

    Adrian Mander, MRC Biostatistics Unit, Cambridge, UK.
    Email adrian.mander@mrc-bsu.cam.ac.uk

References

    R.P.A'Hern (2001) Sample size tables for exact single-stage phase II
    designs. Statistics in Medicine 20:859-866.

    J.Whitehead (2008) Bayesian sample size for exploratory clinical trials
    incorporating historical data. Statistics in Medicine 27:2307-2327.

    T.R. Fleming (1982) One-sample multiple testing procedure for phase II
    clinical trials. Biometrics 38:143-151.

Also see

    Related commands

    HELP FILES              SSC installation links    Description

    samplesize (if installed)    (ssc install samplesize)        Sample Size
    graphics
    sampsi_reg (if installed)    (ssc install sampsi_reg)        Sample Size
    for linear regression
    sampsi_mcc (if installed)    (ssc install sampsi_mcc)        Sample Size
    for matched case/control studies
    sampsi_rho (if installed)    (ssc install sampsi_rho)        Sample Size
    for Pearson correlation