Answer
(c).
Work Step by Step
We can get the number of accidental injuries by summing the numbers of the first column: $295+655+239+363=1552$.
The number of 14-18 year olds is the sum of the numbers in the second row: $655+916=1571$
The expected count can be obtained by multiplying the two obtained numbers and dividing it by $n$: $\frac{1552\cdot1571}{4111}\approx593.09$
The chi-square subtotals can be obtained by squaring the difference between the observed and the expected frequency, divided by the expected frequency: $X_{sub}^2=\frac{(655-593.09)^2}{593.09}\approx6.463$, thus the answer is (c).
