In a finance course at a business school, 6 students are randomly selected. Their mean score on the final exam is 75, with standard deviation 8.

In a finance course at a business school, 6 students are randomly selected. Their mean score on the final exam is 75, with standard deviation 8. 

What is the 95% confidence interval for the average class score on the final?

• [66.6, 83.4]
• [67.6, 82.4]
• [68.6, 81.4]
• [71.7, 78.3]