When Richard Nixon was elected to the US House of Representatives, he attributed his victory to his personal strengths. When defeated by John Kennedy in the 1960 presidential election, however, Nixon's explanations focused on external reasons like the pro-Kennedy bias of the media. This is an example of

The correct answer is self-serving bias

Self-serving bias or egotism is the tendency of individuals to attribute their successes to internal factors, such as intelligence, effort, etc. while they attribute their failures to external factors, such as bad luck or incompetence of others.

Convenience sampling (also known as sampling by sampling, accidental sampling, or sampling of opportunity) is a type of non-probabilistic sampling that involves the sample being extracted from that part of the population that is close to the hand. This type of sampling is most useful for pilot tests.

they had freedom from the government and from the affairs