Statistics from Cornell's Northeast Regional Climate Center indicate that Ithaca, New York, gets an average of 35.4" of rain each year, with a standard deviation of 4.2". Assume that a Normal model applies. 1) During what percentage of years does Ithaca get more than 40" of rain? 2) Less than how much rain falls in the driest 20% of all years? 3) A Cornell University student is in Ithaca for 4 years. Let represent the mean amount of rain for those 4 years. Describe the sampling distribution model of this sample mean, . 4) What 's the probability that those 4 years average less than 30" of rain?
Make a scatterplot of the data. Use 87 for 1987.
1) What does a z-score indicate?
2) What are the three major uses of z-scores with individuals scores?
A privately owned liquor store operates both a drive-in facility and a walk-in facility.
On a randomly selected day, let X and Y, respectively, be the proportions of the time that the drive-in and walk-in facilities are in use, and suppose that the joint density function of these variables is
0, elsewhere.
a. Find the marginal density of X.
b. Find the marginal density of Y.
c. Find the probability that the drive-in facility is busy less than one-half of the time.
The following two-way table displays information about favorite sports cars that resulted from a survey given to all students at Shore High School.
What is the probability that a randomly selected student from this school is a boy?