Answer:
simple random sample
Step-by-step explanation:
The sport columnist generated 150 random numbers and sampled the numbers corresponding to each number of the email list to make sure that there is no bias as all of the email serial numbers have equal chance of being chosen. The sample he got is a simple random sample.
So you see it is the difference of 2 perfect squares
a^2-b^2=(a+b)(a-b)
so
(3b-5)^2-c^2=(3b-5+c)(3b-5-c)
In complex calculations like this, the precedence goes like this
B = Brackets
O = Of (or Exponent)
D = Division
M = Multiplication
A = Addition
S = Substraction
So, in your formula, it will go like this
1/2x3+1/4x2
= 0.5 x 3 + 0.25 x 2
= 1.5 + 0.5
= 2
Hope this helps.