Answer
$0.9624$
Work Step by Step
A score of 86 or higher is deemed as acceptable.
Using the stem-and-leaf display produced in part (a), it will be easer to count the items lower than $86:$
- there is one item with the stem $6$ (representing the score $69)$
- there are three items with the stem $7$ (representing scores $73,74,78),$
- there are three items with the stem $8$, (representing scores $83,84,84)$,
There are $1+3+3=7$ ships with unacceptable sanitation standards.
All other items represent passing scores. The proportion of ships with acceptable sanitation standards is
$\displaystyle \frac{186-7}{186}=0.9624$
