During a routine check of the fluoride content of Gotham City\'s water supply, the following results were obtained from replicate analyses of a single sample: 0.511 mg/L, 0.487 mg/L, 0.511 mg/L, 0.487 mg/L, and 0.519 mg/L Determine the mean and 90% confidence interval for the average fluoride concentration in this sample.
Mean = 0.503mg/L
Find 90% confidence interval