The work is on the picture attached, but a = 1
Hope this helps!!
Range: largest number minus the smallest number
39 - 19 = 20
your range is 20
Mean: add all of the numbers and divide by the amount of numbers there are.
26+19+23+39+31+34+23+25= 220
220/8 = 27.5
your mean is 27.5
hope this helps