You are interested to know if your shop in the suburbs has customers of the same age as your shop in the center of the city. Statistics of customer ages are: Suburbs: X= 38, s = 3.5, n = 19 City Center: 5Z- = 42, s = 4.0 , n = 24
a. Calculate the pooled variance.
b. Test if the ages are same or different using the Z or t test, a = 0.05.