Final answer:
The best point estimate of the population proportion p of respondents feeling vulnerable to identity theft is calculated as p' = x/n = 319/971.
Step-by-step explanation:
The best point estimate of the population proportion p regarding the feeling of vulnerability to identity theft among respondents is the sample proportion (p'). The sample proportion is calculated as the number of respondents who said "yes" divided by the total number of respondents. Using the provided poll data with n = 971 respondents and x = 319 saying "yes", the best point estimate is p' = x/n = 319/971.