Part A

In each of the following situations, identify if it is an observational study or an experiment. Explain your answer.

(a) In an attempt to determine if students prefer bottled water to tap water, you set up a table in the cafeteria at lunchtime and have students sample some of each and ask them which they prefer.

(b) Researchers collect data over 15 years about 100 sets of identical twins to see how their personalities develop similar or different characteristics.

(c) Cloned mice are put into different colored cage environments to see if there is an effect on their temperaments.

(d) Researchers find that babies who were exposed to lead paint have a high risk of brain damage.

Part B

In Lois 2^ndgrade class, all of the students are between 45 and 52 inches tall, except one boy, Lucas, who is 62 inches tall. Which of the following statements is true about the heights of all of the students?

(a) The mean height and the median height are about the same

(b) The mean height is greater than the median height.

(c) The mean height is less than the median height.

(d) More information is needed to answer this question.

(e) None of the above is true.

Explain your answer.

Part C

Enrique has a 91, 87, and 95 for his statistics grades for the first three quarters. His mean grade for the year must be a 93 in order for him to be exempt from taking the final exam. Assuming grades are rounded following valid mathematical procedures, what is the lowest whole number grade he can get for the 4th quarter and still be exempt from taking the exam?

Part D

The UC admissions committee is interested in determining if the number of males and females that are accepted into four-year colleges differs significantly. They take a random sample of 200 graduating high school seniors who have been accepted to four-year colleges. Out of these 200 students they find that there are 134 females and 66 males. Do the numbers of males and females accepted into colleges differ significantly? Since we have a large sample, please calculate the z-score and use a = .05.

Part E

1. In two-way ANOVA, we study not only the effect of two independent variables on the dependent variable, but also the ___ between these variables.

2. We could conduct multiple t-tests between pair of hypotheses but there are several advantages when we conduct a two-way ANOVA. These include:

(a) Efficiency

(b) Control over additional variables

(c) The study of interaction between variables

(d) All of the above