I need help on variability and sampling!! Answer completely and thoroughly

1.In an experimental study, a lab wanted to divide volunteers into two groups to determine the effect of a particular phone app to help make people more punctual (on time). The 50 volunteers in the study will be assigned to either a group of 25 who use the app for a week or a group of 25 who do not use the app. The participants were asked to come to a lab to receive the app (or not) at 10:00 am on a Monday. Answer the following questions:

(a) Why would those performing the study not want to assign the participants in the two treatments (groups) based on who showed up to the study session first?

b) Propose a way to use a random number table to generate a simple random selection that eliminates the bias that you discussed in part (a).

2.Two groups of subjects were divided in an experimental study. One group was given a drug to help speed up their metabolism and result in weight loss. The other group was given a placebo (a pill that looks identical to the one given to the other group, but without the weight loss drug). After a month of the experiment, the weight loss of each individual in each of the two groups were measured. In general, people in the group who took the metabolism drug did lose more weight, although there were differences in the amount each lost. There are two main types of variability occurring in this study. Describe EACH type below in the context of this study.

A) describe Induced Variability

b) describe Natural Variability

3.If you were trying to conduct a survey of political preferences for likely voters in an upcoming election and decided to dial 1,000 randomly generated land-line phone numbers (not cell), why might this still introduce bias into the sampling?