Step 1
The total number of Americans from the poll who opposed the bill where 449 and 258 were not sure.
The total number of Americans in the poll = 1000
Probability is defined as;
[tex]Pr(event)=\frac{number\text{ of required events}}{Total\text{ number of events}}[/tex]Number of required events= Those not in support of the bill = 449+258=707
Total number of events= 1000
Hence the probability that a randomly selected American was not in support of the bill was
[tex]Pr(not\text{ in support of bill\rparen=}\frac{707}{1000}=0.707[/tex]