pwr_grid: powder: A Tidy Extension for Power Analysis

In avallecam/powder: A Tidy Extension for Power Analysis

Description

Create tables and plots for power and sample size calculations from a range of required parameters. All of the parameters accepts a range or sequence of numbers. Usable with pwr and stats::power.

Usage

pwr_grid(
  k = NULL,
  n = NULL,
  n1 = NULL,
  n2 = NULL,
  N = NULL,
  h = NULL,
  f = NULL,
  f2 = NULL,
  r = NULL,
  w = NULL,
  diff = NULL,
  sigma = NULL,
  d = NULL,
  df = NULL,
  u = NULL,
  v = NULL,
  sig.level = 0.05,
  power = NULL,
  type = NULL,
  alternative = NULL
)

pwr_tidy(pwr_grid, test_function)

pwr_plot(pwr_tidy, x, y, group)

Arguments

n	Number of observations (per sample)
diff	Difference between the means
sigma	Standard deviation
d	Effect size (Cohen's d)
sig.level	Significance level (Type I error probability)
power	Power of test (1 minus Type II error probability)
type	Type of t test : one- two- or paired-samples
alternative	a character string specifying the alternative hypothesis, must be one of "two.sided" (default), "greater" or "less"
pwr_grid	outcome of pwr_grid function
test_function	function to calculate power from pwr or stats package
pwr_tidy	outcome of pwr_tidy function
x	x axis
y	y axis
group	colour variable

Value

canal endemico, union y grafico

Functions

• pwr_grid:

• pwr_tidy: create table with parameters and calculations

• pwr_plot: create diagnostic plot

Examples

library(tidyverse)
library(broom)
library(pwr)
library(powder)

# stata
# power onemean 20, diff(10 20 30) sd(10 12.5 15)
eg1 <- pwr_grid(n = NULL,
                diff = c(10,20,30),
                sigma = c(10,12.5,15),
                d = NULL,
                sig.level = 0.05,
                power = 0.8,
                type = "one.sample",
                alternative = "two.sided")

eg1 %>% pwr_tidy(test_function = pwr.t.test)

eg1 %>%
  pwr_tidy(test_function = pwr.t.test) %>%
  pwr_plot(x = diff,y = n,group = sigma)

# stata
# power onemean 20, diff(5 (5) 15) sd(10) n(10 (2) 20)
eg2 <- pwr_grid(n = seq(from = 10,to = 20,by = 2),
                diff = seq(from = 5,to = 15,by = 5),
                sigma = 10,
                d = NULL,
                sig.level = 0.05,
                #power = 0.8,
                type = "one.sample",
                alternative = "two.sided")

eg2 %>% pwr_tidy(test_function = pwr.t.test)

eg2 %>%
  pwr_tidy(test_function = pwr.t.test) %>%
  pwr_plot(x = n,y = power,group=diff)

# stata
# power onemean 100, n(10 20 30) power(0.8) sd(10 12.5 15)
eg3 <- pwr_grid(n=c(10,20,30),
                #diff=c(10,20,30),
                sigma=c(10,12.5,15),
                d=NULL,
                sig.level=0.05,
                power=0.8,
                type="one.sample",
                alternative="two.sided")

eg3 %>% pwr_tidy(test_function = power.t.test)

eg3 %>%
  pwr_tidy(test_function = power.t.test) %>%
  pwr_plot(x = n,y = delta,group=sigma)

avallecam/powder documentation built on March 26, 2021, 4:41 p.m.