For this assignment its not practical to use email as there will be graphing involved. So waste some trees and use paper.

For this homework assignment, you may work with 1 or 2 other students in class to complete it.

Questions:

1. Here is some data on coal exports for three countries from 1975 to 1990. The units are in Millions of Tons:

Year US Canada South Africa 1975 65 17 3 1976 60 17.6 3.5 1977 58 18 17.5 1978 40 19 19 1979 62 19 22 1980 84 19.5 28 1981 103 20.0 33 1982 102 18 29 1983 78 20 34 1984 83 26 40 1985 94 31 48 1986 87 28 46 1987 80 32 42 1988 97 38 44 1989 101 40 51 1990 110 35 59

a) For each country plot the frequency distribution of exports in each year and determine the average.

b) On the same graph and using different symbols or colors or whatever, For each country plot tons exported vs year.

c) Since 1983, Which country shows the most abrupt increases in coal exports?

d) Based on the data, predict how much total coal each country is likely to export from 1991-2000.

*The following questions should be considered as practice for the
first Midterm. *

2. You get a job counting cars on the Ferry street bridge in order to improve traffic flow. After 1 month you have established the following:

The average number of cars that cross the bridge between 4 and 6 pm is 20,000 The dispersion around this average is 4,000 cars.

a) What is the probability that during 4 and 6 pm there will be more than 25,000 cars that cross the bridge?

b) What is the probability that during 4 and 6 pm there will be more than 30,000 cars that cross the bridge?

c) What is the probability that during 4 and 6 pm there will be more than 40,000 cars that cross the bridge?

3,4,6,10,3,2,8,13,7,6,12,9,13,5,4,8,6,11,3,5

a) What is the mean flood level?

b) What is the 100 year flood stage based on this data?

4. A survey of 25 gas stations in the Eugene Area showed an average price for unleaded gas of $1.25 per gallon with a dispersion of 10 cents. A survey of 25 stations in the Portland area had an average of $1.35 per gallon with a dispersion of 10 cents. A survey of 49 stations in the Seattle area had an average of $1.30 per gallon with a dispersion of 21 cents. Use this data for the following questions (show your work!):

a) What is the probability that in Eugene you will pay more than $1.45 per gallon?

b) What is the probability that in Portland you will pay more than $1.45 per gallon?

c) Which location has the highest probability of paying $1.50 or more per gallon.

d) Is the price of gas significantly higher in Portland than Eugene?

e)Is the price of gas significantly higher in Seattle than Eugene?

f) About how many gas stations would I have to go to in Eugene to find a price of less than $1.00 per gallon?

g) In what location would I have the highest probability of finding a price of less than $1.00 per gallon?