To find the mean, we sum up all the times and divide by the number of times in the group.
For Group A:
Mean = (18 + 20 + 46 + 34 + 58 + 31 + 41) / 7 = 248 / 7 = 35.4 minutes
For Group B:
Mean = (15 + 21 + 32 + 42 + 29 + 57 + 39) / 7 = 235 / 7 = 33.6 minutes
The mean time Group A spent shopping is 35.4 minutes.
The mean time Group B spent shopping is 33.6 minutes.
The difference in the mean times is:
35.4 - 33.6 = 1.8 minutes
Therefore, the mean time Group A and Group B spent shopping is 1.8 minutes.