Posted by Kitty on .
Random samples were taken over 2 weeks (14 days) of a drink machine and data was collected of each drink sold. The sample mean was 65.2 drinks with a deviation of 8.1 drinks. Construct a 95% confidence interval on the mean number of drinks sold per day.

Math 
PsyDAG,
95% = mean ± 1.96 SEm
SEm = SD/√n
I'll let you do the calculations.