The dot plot below shows the amount of time two random groups of students took to brush their teeth:

A dot plot shows Tooth Brushing Time in seconds on the horizontal axis. For Group R, there is 1 dot on 45, 2 dots on 50, 1 dot on 55, 2 dots on 60, 1 dot on 65, 1 dot on 70, 1 dot on 75, 1 dot on 80, 1 dot on 85, 2 dots on 90, 1 dot on 95, 2 dots on 100, 1 dot on 105, 2 dots on 110, 1 dot on 115, and 2 dots on 120. For Group S, there is 1 dot on 50, 1 dot on 55, 2 dots on 60, 2 dots on 70, 1 dot on 80, 2 dots on 90, 1 dot on 95, 1 dot on 100, 1 dot on 105, 2 dots on 110, 1 dot on 115, and 1 dot on 120.

Based on visual inspection of the dot plots, which of the following groups, if any, shows a greater average time required to brush their teeth?

Group R
Group S
Both groups show about the same average time.
No conclusion about average time can be made from the data.