Item$9$

$10$

points

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Problem $10-20($Static$)$

A teller at a drive$-$up window at a bank had the following service times $($in minutes$)$ for $20$ randomly selected customers:

SAMPLE

$1234$

$4\mathrm{.}54\mathrm{.}64\mathrm{.}54\mathrm{.}7$

$4\mathrm{.}24\mathrm{.}54\mathrm{.}64\mathrm{.}6$

$4\mathrm{.}24\mathrm{.}44\mathrm{.}44\mathrm{.}8$

$4\mathrm{.}34\mathrm{.}74\mathrm{.}44\mathrm{.}5$

$4\mathrm{.}34\mathrm{.}34\mathrm{.}64\mathrm{.}9$

b$.$ If the process parameters are unknown, estimate its mean and standard deviation. $($Round "Mean" value to $1$ decimal place and "Standard deviation" value to $3$ decimal places.$)$