Confidence-interval width planning functions

Determines the sample size required to achieve a target total confidence interval width for selected interval procedures.

Usage

n_width_mu_z(w, sigma, conf.level = 0.95, digits = 4, quiet = FALSE)

n_width_p_wald(
  w,
  conf.level = 0.95,
  p = 0.5,
  worst_case = TRUE,
  digits = 4,
  quiet = FALSE
)

n_width_mu_t(
  w,
  s,
  conf.level = 0.95,
  n_start = NULL,
  max_iter = 100,
  digits = 4,
  quiet = FALSE
)

Arguments

w

Target total confidence-interval width.

sigma

Known population standard deviation input.

conf.level

Confidence level in (0, 1).

digits

Integer number of decimal places used only for printed output.

quiet

Logical; if TRUE, suppress printed output.

p

Planning value for a proportion.

worst_case

Logical; if TRUE, use the worst-case proportion value.

s

Sample standard deviation used for t-based width planning.

n_start

Starting sample size for iterative width planning.

max_iter

Maximum number of search iterations.

Details

These functions return classed result objects with unrounded stored values and optional printed summaries controlled by digits and quiet.

Functions

• n_width_mu_z(): Required sample size for a z interval for a mean.

• n_width_p_wald(): Required sample size for a Wald interval for a proportion.

• n_width_mu_t(): Required sample size for a t interval for a mean.