Answer:
a) 40 is the interquartile range
descriptive statistics, the interquartile range, also called the midspread, middle 50%, or H‑spread, is a measure of statistical dispersion, being equal to the difference between 75th and 25th percentiles, or between upper and lower quartiles, IQR = Q₃ − Q₁.
b).
The first thing you always need to do before estimating fractions is to round each fraction either to the nearest 0, 1/2, or 1. Example #1. Estimate 3/7 + 5/9. Notice that 3/7 is close to 1/2 and 5/9 is also close to 1/2. Therefore, an estimate for 3/7 + 5/9 is 1/2 + 1/2 = 1.
