A simple random sample of students is selected, and the students are asked how much time they spent preparing for a test. The times (in hours) are as follows:
1.3 7.2 4.2 12.5 6.6 2.5 5.5
Based on these results, a confidence interval for the population mean is found to be μ = 5.7 ± 4.4. Find the degree of confidence.