# Bill Qualls
# NW - Stats II - Lab 1 - #3
# This is NW2-1-3.MTB
# 3. Invoices at a particular depot have amounts which follow a normal distribution
# with a mean invoice of $110.70 and a standard deviation of $7.85.
# Recall standard normal has mean=0 and stdev=1.
# Since this is not a standard distribution, we need to specify mean and stdev.
# The cdf instuction gives the area to the left of x.
# To get the area to the right of x, subtract cdf from 1.
# To get the area between two x scores, subtract their cdfs.
# Asign a constant to a variable starting with k: k1, k2, k3, ...
# What percentage of invoices will be over $130.25?
# Must use the cdf command and the normal subcommand.
# Note the semicolon on the first line, indicating a subcommand
# will follow, and a period on the second indicating end.
# Reminder: for "over", subtract cdf from 1
cdf 130.25;
normal 110.70 7.85.
let k1 = 1 - 0.9936
print k1
# What percentage of invoices will be below $91.50?
# Reminder: for "below", no other calculation is needed.
cdf 91.50;
normal 110.70 7.85.
print k1
# What percentage of invoices will be between $87.25 and $118.30?
# Reminder: for "between", subtract low cdf from high cdf.
cdf 87.25;
normal 110.80 7.85.
cdf 118.30;
normal 110.80 7.85.
let k1 = 0.8303 - 0.0013
print k1
stop