From the plot, the masses of the five smallest sodium chloride samples are all 1/4 ounce. Therefore, we can calculate for their total mass by multiplying the mass by 5:
total mass = 1/4 ounce * 5
= 5/4 or 1.25 ounces
We can get the same result even if we compute for the total mass by taking the sum of their masses:
total mass = 1/4 + 1/4 + 1/4 + 1/4 + 1/4
= 5/4 oz.
