Required Sample Size
Function to determine required sample size to be within a given margin of error.
nsize(b, sigma = NULL, p = 0.5, conf.level = 0.95, type = "mu")
b |
the desired bound. |
sigma |
population standard deviation. Not required if using type
|
p |
estimate for the population proportion of successes. Not required
if using type |
conf.level |
confidence level for the problem, restricted to lie between zero and one. |
type |
character string, one of |
Answer is based on a normal approximation when using type "pi".
Returns required sample size.
Alan T. Arnholt
nsize(b=.03, p=708/1200, conf.level=.90, type="pi")
# Returns the required sample size (n) to estimate the population
# proportion of successes with a 0.9 confidence interval
# so that the margin of error is no more than 0.03 when the
# estimate of the population propotion of successes is 708/1200.
# This is problem 5.38 on page 257 of Kitchen's BSDA.
nsize(b=.15, sigma=.31, conf.level=.90, type="mu")
# Returns the required sample size (n) to estimate the population
# mean with a 0.9 confidence interval so that the margin
# of error is no more than 0.15. This is Example 5.17 on page
# 261 of Kitchen's BSDA.Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.