Of the following four scenarios, which survey results are likely to be the most statistically significant and which are likely to be the least statistically significant? Explain your answer.

Scenario 1: 1,000 students are surveyed after completing six months of a basic French language course to see if they have learnt the usage of prepositions in French.

Scenario 2: 50 businessmen are surveyed to see whether their marketing skills have improved after attending a week-long seminar on innovative techniques of marketing.

Scenario 3: 700 workers, who have been working for over 30 years in the cashew industry, are surveyed for a study to determine if shelling the cashew nuts by hand has led to a medical diagnosis of dermatitis, which is a chronic skin condition. 

Scenario 4: In a study to see if Coldplay’s fans or Metallica’s fans spend more, 20 people from each fanbase are surveyed before they enter their respective stadiums for the concerts.