With yx = zx, then by the Multiplicative Property of Equality, y = z. Since z is a negative integer, then y is also a negative integer. Since yx is positive, with y equal to a negative integer, then x is negative.
The method applied in this scenario is called simple random sampling. A sample of 100 customers is chosen from a larger population of customers and each customer has the same chance of being selected for the survey at any given time. Also, the chance of selecting 100 customers from each store is the same during the sampling process. The order of sampling at each store does not follow a certain order, thus, It is different from systematic random sampling.
