Answer:
a. Rounded b. Start at 1,100,000 on the vertical axis and go to 1,300,000, skipping by 25,000 every tick
Explanation:
a. The more digits a value has, the more precise your dot placement should be. And because all the values have 7 digits, it would be too painful to plot the exact values because you would have to be extremely precise. So rounding them to the nearest hundred thousandths (the 6th digit) would be appropriate.
b. The smallest value not less than 1,100,000, so the lowest acceptable number on the vertical axis is 1,100,000, and the largest value is not greater than 1,300,000, so the greatest acceptable number on the vertical axis is 1,300,000. And as for how much you should skip by every tick, a good rule of thumb is to just have about 7 - 15 ticks total on your vertical axis. Therefore, you kind of just have to trial-and-error how much you should skip each tick by. For example, I picked 25,000 because by doing so I got 9 ticks total, so it was good enough. (And the larger your graph is, the more ticks you could add to the vertical axis. So if you had a comically small piece of paper, you wouldn't have enough space to even get to 7 ticks without it looking clustered. And if you had a comically large piece of paper, you would have so much space that even with 15 ticks it would still look too dispersed)