An article in the Journal of Sports Science presents the results of an investigation of the hemoglobin level of Canadian Olympic ice hockey players. A random sample of 20 players is selected and the hemoglobin level is measured. The resulting sample mean and standard deviation(g/dl) are 15.40 for the mean and 0.6137 for the standard deviation.

Use this information to calculate a 95% two-sided confidence interval on the mean hemoglobin level.

Assume the data is normally distributed.