There are 100 points on this test. Show all your work so that I can award partial credit if necessary. Put your names and answers on the separate blank sheets I will pass out.
(50 pts total) All parts of this problem refer to the following dataset.
(10 pts) Compute the mean and standard deviation for x
(10 pts) Compute the mean and standard deviation for y.
(10 pts) Compute the correlation of the two variables.
(5 pts) Describe the strength and direction of the association between x and y.
(10 pts) Find the equation of the least-squares regression line, using x as the explanatory variable and y as the response variable
(5 pts) Use the equation from the previous question to predict the y value for an x value of 2.3.
(20 pts total—5 points each part) The following table of statistics,
boxplot, and normal quantile plot were created in CrunchIt to
summarize a dataset of the number of words spoken per day by
the men in a study of speech patterns of 42 women and 37 men.
Is the distribution of the WordsPerDay variable roughly normal? Support your answer.
Is the distribution of the WordsPerDay variable right-skewed, left-skewed, or not skewed? Support your answer.
Are there any outliers, according to the 1.5 * IQR rule?
Which is a better measure of center for this data set—the mean or the median?
What is the z-score for x = 15,000 words?
Use Table A from the textbook to calculate the percentage of college professors that speak 15,000 words per day or more.
Summarize the data in a two-way table
What is the marginal distribution of rarely using a
calculator when doing homework?