aipe.smd | R Documentation |

A set of functions that `ss.aipe.smd`

calls upon to calculate the appropriate sample size
for the standardized mean difference such that the expected value of the confidence interval
is sufficiently narrow.

```
ss.aipe.smd.full(delta, conf.level, width, ...)
ss.aipe.smd.lower(delta, conf.level, width, ...)
ss.aipe.smd.upper(delta, conf.level, width, ...)
```

`delta` |
the population value of the standardized mean difference |

`conf.level` |
the desired degree of confidence (i.e., 1-Type I error rate) |

`width` |
desired width of the specified (i.e., |

`...` |
specify additional parameters in functions these functions call upon |

`n` |
The necessary sample size |

The returned value is the sample size *per group*. Currently only
`ss.aipe.smd.full`

returns the exact value. However, `ss.aipe.smd.lower`

and `ss.aipe.smd.upper`

provide approximate sample size values.

The function `ss.aipe.smd`

is the function users should generally use. The function
`ss.aipe.smd`

calls upon these functions as needed. They can be thought of loosely
as internal MBESS functions.

Ken Kelley (University of Notre Dame; KKelley@ND.Edu)

Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum.

Cumming, G. & Finch, S. (2001). A primer on the understanding, use, and calculation of confidence intervals that are
based on central and noncentral distributions, *Educational and Psychological Measurement, 61*, 532–574.

Hedges, L. V. (1981). Distribution theory for Glass's Estimator of effect size and related estimators. *Journal of Educational Statistics, 2*, 107–128.

Kelley, K. (2005). The effects of nonnormal distributions on confidence intervals around the standardized mean
difference: Bootstrap and parametric confidence intervals, *Educational and Psychological Measurement, 65*, 51–69.

Kelley, K., Maxwell, S. E., & Rausch, J. R. (2003). Obtaining Power or Obtaining Precision: Delineating Methods
of Sample-Size Planning, *Evaluation and the Health Professions, 26*, 258–287.

Kelley, K., & Rausch, J. R. (2006). Sample size planning for the standardized mean difference:
Accuracy in Parameter Estimation via narrow confidence intervals. *Psychological Methods, 11(4)*, 363–385.

Steiger, J. H., & Fouladi, R. T. (1997). Noncentrality interval estimation and the evaluation of
statistical methods. In L. L. Harlow, S. A. Mulaik, & J.H. Steiger (Eds.), *What if there were
no significance tests?* (pp. 221–257). Mahwah, NJ: Lawrence Erlbaum.

`ss.aipe.smd`

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