Recently on the Comedy Channel a female Canadian comic asked the following question:
"When you are out at a bar have you ever noticed that after four or five drinks all the ugly people seem to have gone home?"
The premise of her question is that alcohol consumption alters our perception of attractiveness. Imagine that an experimenter wanted to determine if this change in our perception of attractiveness was related to our experience with alcohol. To test this idea s/he collected the following data from 25 experienced drinkers and 25 inexperienced drinkers. Each of the numbers below is the number of drinks (1 ounce shots) required to alter the participant's perception of attractiveness.
Experienced Drinkers:
8, 7, 2, 1, 6, 7, 7, 5, 8, 5, 4, 7, 7, 6, 6, 3, 6, 6, 3, 8, 4, 2, 5, 6, 6
Inexperienced Drinkers:
8, 5, 4, 4, 3, 3, 2, 6, 2, 3, 1, 6, 3, 2, 4, 5, 4, 4, 3, 4, 5, 7, 5, 5, 4
Answer the following four questions based on the data above.
A. What is the dependent variable and what is the independent (or quasi-independent) variable in this study?
B. As measured in this study is the dependent variable continuous or discrete, and what type of scale was used to measure it?
C. Plot the data from both the Experienced Drinkers and the Inexperienced Drinkers in a single polygon graph. Be sure to clearly label your axes and to indicate which curve belongs to which group.
D. Calculate the unbiased standard deviation for the Experienced Drinkers only.
2. Imagine you took three exams with the following results:
Exam Your Score m s
Intro to Psych 85 82 10
Statistics 80 75 8
English 80 90 12
What appears to be your strongest subject area and how did you come to this conclusion?
3. You walk into statistics class one day and find that you're having a pop quiz. Looking at the exam, you find that there are 72 multiple-choice questions with three possible responses (A, B, or C) for each, where only one is correct. The passing grade is set at 50%. Unluckily for you, you haven't been to a single class before this, nor have you ever opened the textbook. Actually, you can't even say for sure who the guy is at the front of the class. You will have to guess the answer on all the questions. What is the probability that you will pass the exam?