Me
4. charlie's automotive dealership is considering implementing a new check-in procedure on
are bringing their vehicles for routine maintenance. the dealership will launch the procedura
• the dealership will launch the procedure if 50% or more of
the customers give the new procedure a favorable rating when compared to the current procedu
dealership devises a simulation based on the minimal requirement that 50% of the customers prior to
procedure. each dot on the graph below represents the proportion of the customers who preferred the
check-in procedure, each of sample size 40, simulated 100 times.
ew
mean = 0.506
sd = 0.078

0.30
0.35
0.400.450.500.550.600.65
proportion preferring new procedure
0.70
assume the set of data is approximately normal and the dealership wants to be 95% confident of its results.
using the results from the simulation, determine an interval containing the plausible sample values for which
the dealership will launch the new procedure. round your answer to the nearest hundredth. forty customers
are selected randomly to undergo the new check-in procedure and the proportion of customers who prefer the
new procedure is 32.5%. the dealership decides not to implement the new check-in procedure based on the
results of the study. use statistical evidence to explain this decision.