An experiment is performed to compare the rotational speed of two conveyers, Conveyer \(X\) and Conveyer \(Y\). 30 belts are loaded with an optimal weight, each is put on one of the conveyers, and the speed of the conveyer is measured. Criticize the following aspects of the experiment.

(a) To accelerate the testing procedure, highperformance motors are used and movement is measured in 30-second intervals.

(b) The entire experiment is performed with loads of elongated objects.

(c) The speeds of all observations of Conveyer \(X\) are taken first.

(d) 10 of the belts are put on Conveyer \(X\) and 20 on Conveyer \(Y\).