**In the graph below, in the time colum, where it says the letter z, that means the less than and equal to sign. Where is says the letter s, that means the less than sign.**

Time (t)15 z t s 2121 z t s 27 27 z t s 33 33 z t s 39 39 z t s 45 |
Frequency (f)610 5 3 1 Total = 25 |
Midpoint (x)1824 30 36 42 |
F x X108240 150 108 42 |

**When you are 'Estimating the mean', the graph will have the first colum so in this case 'the Time colum ' and the Frequency colum. You need to find the midpoint and FxX. To find the midpoint you add the two numbers in the first colum. So, we would add 15 and 21 which equals 36. You then divide by 2 which is 18. That is your answer. To find FxX you do frequency which is f, times by midpoint which is x. That is your FxX.**