Description Usage Arguments See Also Examples

Power calculations for t-test

1 2 3 |

`es` |
effect size. |

`n` |
total number of observations/pairs |

`power` |
power of study |

`sig.level` |
significance level |

`ratio` |
the ratio of sample size 1 to sample size 2. Only will be used when 'type' is "unequal". |

`type` |
type of t test, must be one of "one","two" (default), "paired", or "unequal". "one" means one sample t test, which test whether the population mean is equal to a specified value. "two"/"unequal" means two sample (equal size/unequal size) t test, which is used to ascertain how likely an observed mean difference between two groups would be to occur by chance alone. "paired" means paired t-test (also called the correlated t-test and the t-test for dependent means), which is used to ascertain how likely the difference between two means that contain the same (or matched) observations is to occur by chance alone. |

`alternative` |
One- or two-sided test, must be one of "two.sided" (default), "left", "right" |

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | ```
## one sample two sided test, calculate power
power.t(es=0.2,n=60,sig.level=0.10,type="one",alternative="two.sided")
## one sample one sided (left tail) test, calculate power
power.t(es=0.2,n=60,sig.level=0.10,type="one",alternative="left")
## one sample one sided (right tail) test, calculate power
power.t(es=0.2,n=60,sig.level=0.10,type="one",alternative="right")
## one sample two sided test, calculate sampe size
power.t(es=0.2,power=0.8,sig.level=0.05,type="one",alternative="two.sided")
## one sample two sided test, calculate effect size
power.t(n=200,power=0.8,sig.level=0.05,type="one",alternative="two.sided")
## one sample two sided test, calculate sig.level
power.t(es=0.2,n=200,power=0.8,type="one",alternative="two.sided")
## paired sample two sided test, calculate power
power.t(es=0.559,n=40,sig.level=0.05,type="paired",alternative="two.sided")
## paired sample two sided test, calculate sample size
power.t(es=0.15,power=0.8,sig.level=0.05,type="paired",alternative="two.sided")
## paired sample two sided test, calculate effect size
power.t(n=200,power=0.8,sig.level=0.05,type="paired",alternative="two.sided")
## two sample two sided test, calculate power
power.t(es=0.15,n=300,sig.level=0.05,type="two",alternative="two.sided")
## two sample two sided test, calculate sample size
power.t(es=0.15,power=0.8,sig.level=0.05,type="two",alternative="two.sided")
## two sample two sided test, calculate effect size
power.t(n=300,power=0.8,sig.level=0.05,type="two",alternative="two.sided")
## two sample (unequal size), calculate sample size
power.t(es=0.15,power=0.8,sig.level=0.05,type="unequal",ratio=2,alternative="two.sided")
power.t(es=0.1,n=3000,sig.level=0.05,type="unequal",ratio=2,alternative="two.sided")
``` |

```
One-sample t test power calculation
es = 0.2
n = 60
power = 0.4555818
sig.level = 0.1
alternative = two.sided
NOTE: n is the number of observations
One-sample t test power calculation
es = 0.2
n = 60
power = 0.002400866
sig.level = 0.1
alternative = left
NOTE: n is the number of observations
One-sample t test power calculation
es = 0.2
n = 60
power = 0.6013403
sig.level = 0.1
alternative = right
NOTE: n is the number of observations
One-sample t test power calculation
es = 0.2
n = 198.1508
power = 0.8
sig.level = 0.05
alternative = two.sided
NOTE: n is the number of observations
One-sample t test power calculation
es = 0.1990655
n = 200
power = 0.8
sig.level = 0.05
alternative = two.sided
NOTE: n is the number of observations
One-sample t test power calculation
es = 0.2
n = 200
power = 0.8
sig.level = 0.04851422
alternative = two.sided
NOTE: n is the number of observations
Paired t test power calculation
es = 0.559
n = 40
power = 0.931511
sig.level = 0.05
alternative = two.sided
NOTE: n is number of *pairs*
Paired t test power calculation
es = 0.15
n = 350.7638
power = 0.8
sig.level = 0.05
alternative = two.sided
NOTE: n is number of *pairs*
Paired t test power calculation
es = 0.1990655
n = 200
power = 0.8
sig.level = 0.05
alternative = two.sided
NOTE: n is number of *pairs*
Two-sample (equal size) t test power calculation
es = 0.15
n = 300
power = 0.4500203
sig.level = 0.05
alternative = two.sided
NOTE: n is number in *each* group
Two-sample (equal size) t test power calculation
es = 0.15
n = 698.6382
power = 0.8
sig.level = 0.05
alternative = two.sided
NOTE: n is number in *each* group
Two-sample (equal size) t test power calculation
es = 0.2291204
n = 300
power = 0.8
sig.level = 0.05
alternative = two.sided
NOTE: n is number in *each* group
Two-sample (unequal size) t test power calculation
es = 0.15
power = 0.8
n = 1571.695
n1 = 1047.797
n2 = 523.8984
ratio = 2
sig.level = 0.05
alternative = two.sided
NOTE: n is the total number of observations
Two-sample (unequal size) t test power calculation
es = 0.1
power = 0.732768
n = 3000
n1 = 2000
n2 = 1000
ratio = 2
sig.level = 0.05
alternative = two.sided
NOTE: n is the total number of observations
```

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