The range gives the spread of data. To find the range, you first need to find the lowest and highest values in the data. The range is found by subtracting the lowest value from the highest value.
3) Group A has the age similar to 10 as the range is 3 so the age could be in the range 7-10 --> 10-13. Group A has a large range with a mean age of 10, this implies that the range of ages could be in 3-10 --> 10-17.
4) Chris should choose type A battery as the range is lower. This means that the values are close to 15 hours and would not have large outliers (Range of hours could be 12-18). Type B has a mean of 15 hours but the range is 6 so it may mean that the lowest hour could be 9 hours but the highest value could be 24 hours.