Question

Question 1: If R squared=0.64 for the linear regression equation Y= 3.2X+ 2.8 + error , Where Y (or response variable) = stopping distance and X (or explanatory variable)= Velocity which of the following are true?

1. a.) That 64 % of the variation in Stopping distance is explained by velocity and the correlation coefficient R= -0.8
2. b.) That 64 % of the variation in Stopping distance is explained by velocity and the correlation coefficient R= 0.8
3. c.) That velocity (X) will explain the stopping distance perfectly 64% of the time and the correlation coefficient is R= 0.7
4. d.) That velocity (X) will explain the stopping distance perfectly 64% of the time and the correlation coefficient is R= 0.7

Question 2: Which of the following is true about categorical and quantitative variables

1. a.) That pie charts and bar charts provide a good description of quantitative variables but not categorical variables
2. b.) That histograms and stem and leaf plots provide a good description of quantitative variables but not categorical variables
3. c.) Both a and b

Question 3: Which of the following is true about skewed distributions?

1. a.) That the closer the mean is to the median the more skewed the data is.
2. b.) That the mean and median is the same whether the distribution is skewed or normal.
3. c.) That you can’t rely on just on whether the mean= median to see if you have zero skewness, you have to see if your histograms and stem and leaf plot are symmetrical or normally distributed as well to assess if your data is truly normal.
4. d.) The closer the mean is to the median the more normal the data is
5. e.) Both c and d.
6. f.) All of the above

Question 4: Use your normal probability chart to find the probability of the below:

1. a.) P( Z < -1.21) b.) P( Z > - 1.21)    c.) P(Z < 2.13)      d) P( Z > 2.13)

Answer 1