You ask your friends who they plan to vote for in the next congressional election. Based on their responses, you conclude that the candidate you favor cannot lose! This is most likely an example of

sampling bias

Explanation:

You ask your friends who they plan to vote for in the next congressional election. Based on their responses, you conclude that the candidate you favor cannot lose! This is most likely an example of sampling bias.

The sampling should be distributed among a wider range of people to avoid bias. Your friends most likely have the same opinion like you and as such basing your conclusion on their opinion is biased. To achieve a more likely and unbiased result, you should use a larger sample size which does not include friends, family members and close associates and in different locations, The result from such sampling will be more representative of public opinion.