1. In an experiment, participants are usually assigned to treatments ising a random assignment procedure. Why is random assigment used?2. A reasearcher wants to know if brighter lights make factory workers more productive. Workers in a factory are randomly assigned to two groups. One group is moved to a new factory next door, where the factory lights are brighter. The other group stays behind in the old factory. The productivity if the two groups is comepared.3. What is the independent variable(s)? What is the dependent variables(s)? What is the plausible confounding variable in this study?

The two-way table below shows teenage driver gender and whether or not the respondent had texted at least once while driving during the last thirty days. Teenage driver- Teenage driver- Male Female Texted at least once while driving during past 30 days. Had not texted at least once while 7 11 9 driving during the past 30 days. What percentage of the sample had texted at least once while driving in the past thirty days? O 37.5% O 62.5% De O 50% O 43.75%

2. In a population it is estimated that 20% have a desired trait of interest for the researcher. The researcher wants to know how many people on average he has to draw from a population to get 2 people with the trait. Use rows 20-24 of the Random Number Table to carry out the simulation. Explain clearly how you set up the problem and report your findings. Answer:

When computing the variance using a sample of size n = 30, we divide the sum of squared deviations by Give your answer as a whole number.

A research paper describes an experiment in which 74 men were assigned at random to one of four treatments. 1. viewed slides of fit, muscular men 2. viewed slides of fit, muscular men accompanied by diet and fitness-related text 3. viewed slides of fit, muscular men accompanied by text not related to diet and fitness 4. did not view any slides The participants then went to a room to complete a questionnaire. In this room, bowls of pretzels were set out on the tables. A research assistant noted how many pretzels were consumed by each participant while completing the questionnaire. Data consistent with summary quantities given in the paper are given in the following table. Treatment 1 9 6 4 13 1 2 5 9 12 5 2 0 7 4 10 6 0 11 Treatment 2 Treatment 3 7 8 0 3 9 8 7 1 6 8 8 5 13 9 0 7 4 11 5 7 10 8 7 1 10 2 5 1 0 3 0 3 4 4 5 5 6 8 4 0 7 3 Treatment 4 5 2 5 7 5 2 0 0 4 3 2 3 1 1 Do these data provide convincing evidence that the means for the numbers of pretzels consumed are not the same for…