Dorben Co$.$ provides a $10\%$ allowance for its operators. A work sampling study of one

operator over an $8-$hour shift yields the following data. The average rated performance is

$110\%.$ The expected output is $50$ units$/$shift$.$

a$)$ Calculate the observed time in minutes for loading $($min$/$unit$)$

b$)$ Calculate the normal time for unloading $($min$/$unit$)$

c$)$ What is the overall standard time $($min$/$unit$)$

d$)$ What is the accuracy of the study $(95\%$ confidence$)$