Answer
a. left endpoints: $\approx 24.2844 $ people
right endpoints: $\approx 28.2296 $ people
b. The x-axis of the curve would be the date, while the y-axis would be the deaths per day. Thus, when taking the area under this curve, one would get the number of people who died from SARS in a certain period of time.
Work Step by Step
Since the table records data taken from two-week intervals, you know that the length of each approximating rectangle and 14 days (2 weeks).
a. left endpoints: $$ 14* (0.0079+ 0.0638+ 0.1944+0.4435+0.5620+0.4630)\approx 24.2844$$ You ignore the last data point, as you're taking rectangles starting from the first data point.
right endpoints: $$ 14* (0.0638+ 0.1944+0.4435+0.5620+0.4630 + 0.2897)\approx 24.2844$$You ignore the first data point, as you're taking rectangles starting from the last data point.
b. Imagine the "date" column as being the x-axis, and the "deaths per day" column as being the y-axis.
