# NOT RUN {
# Generate 100 observations from a zero-modified normal distribution
# with mean=4, sd=2, and p.zero=0.5, then estimate the parameters.
# According to equations (1) and (2) above, the overall mean is
# mean.zmnorm=2 and the overall standard deviation is sd.zmnorm=sqrt(6).
# (Note: the call to set.seed simply allows you to reproduce this example.)
set.seed(250)
dat <- rzmnorm(100, mean = 4, sd = 2, p.zero = 0.5)
ezmnorm(dat, ci = TRUE)
#Results of Distribution Parameter Estimation
#--------------------------------------------
#
#Assumed Distribution: Zero-Modified Normal
#
#Estimated Parameter(s): mean = 4.037732
# sd = 1.917004
# p.zero = 0.450000
# mean.zmnorm = 2.220753
# sd.zmnorm = 2.465829
#
#Estimation Method: mvue
#
#Data: dat
#
#Sample Size: 100
#
#Confidence Interval for: mean.zmnorm
#
#Confidence Interval Method: Normal Approximation
# (t Distribution)
#
#Confidence Interval Type: two-sided
#
#Confidence Level: 95%
#
#Confidence Interval: LCL = 1.731417
# UCL = 2.710088
#----------
# Following Example 9 on page 34 of USEPA (1992c), compute an
# estimate of the mean of the zinc data, assuming a
# zero-modified normal distribution. The data are stored in
# EPA.92c.zinc.df.
head(EPA.92c.zinc.df)
# Zinc.orig Zinc Censored Sample Well
#1 <7 7.00 TRUE 1 1
#2 11.41 11.41 FALSE 2 1
#3 <7 7.00 TRUE 3 1
#4 <7 7.00 TRUE 4 1
#5 <7 7.00 TRUE 5 1
#6 10.00 10.00 FALSE 6 1
New.Zinc <- EPA.92c.zinc.df$Zinc
New.Zinc[EPA.92c.zinc.df$Censored] <- 0
ezmnorm(New.Zinc, ci = TRUE)
#Results of Distribution Parameter Estimation
#--------------------------------------------
#
#Assumed Distribution: Zero-Modified Normal
#
#Estimated Parameter(s): mean = 11.891000
# sd = 1.594523
# p.zero = 0.500000
# mean.zmnorm = 5.945500
# sd.zmnorm = 6.123235
#
#Estimation Method: mvue
#
#Data: New.Zinc
#
#Sample Size: 40
#
#Confidence Interval for: mean.zmnorm
#
#Confidence Interval Method: Normal Approximation
# (t Distribution)
#
#Confidence Interval Type: two-sided
#
#Confidence Level: 95%
#
#Confidence Interval: LCL = 3.985545
# UCL = 7.905455
#----------
# Clean up
rm(dat, New.Zinc)
# }
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