Chapter PIII, Problem 22RE

(a)

To determine

To Explain: that this is a experiment or study.

Explanation of Solution

This was an experimental study because it manipulates the one factor that is radio waves and produces the treatments and assigns subject to these treatment levels randomly, meaning that as a result of the three treatments, it has three levels that are digital cell phone radio waves, traditional cell phone radio waves and no radio waves. The occurrence of brain tumours is the liable predictor.

(b)

To determine

To Explain: the meaning of not statistically significant.

Explanation of Solution

Not statistically relevant in this sense means that the disparity in tumour incidence between three groups of rats was not sufficient to convince researchers that the differences were due to something other than variability in sampling.

(c)

To determine

To explain: the fact that Motorola, a mobile phone maker, sponsored this study.

Explanation of Solution

This research was discovered by Motorola. A mobile phone maker who may have demonstrated bias. The researchers in this experiment have felt the urge to announce that the mobile phone is safe.