The typical American generates about 3.8 pounds
of solid trash per day with standard deviation of 1.5 pounds.
Assuming that the histogram for trash produced per day is
approximately bell-shaped, between what two
values will 95% of the observations fall?
3.
The following data are the monthly rental prices (in dollars) for a sample of
15 unfurnished 2-bedroom apartments off-campus.
Obtain a histogram and boxplot with your TI-83. What is the shape?
(c)
Based on the information you've gathered so far, how would you
answer the question ``How much should I expect to pay for an unfurnished
2-bedroom apartment off-campus?''.
(d)
If you are to choose between the average and median, which do you think
is a better measure of location for this data set? Why?
4.
Consider the following histogram. Suppose 95% of the data falls between
12.4 and 46.8. Using the empirical rule, give an estimate of the standard
deviation for this sample of data.
A random sample of 10 different unfurnished 1-bedroom apartments off-campus yield
an average monthly rent of $500 with SD $100. A second sample of
10 2-bedroom apartments yield an average rent of $650 with SD
$100.
(a)
Suppose that WMU students get a $20 discount on the monthly rent for all
1-bedroom apartments. The discounted monthly rent for the sample of 1-bedroom apartments
should yield an average of ________________ with SD
________________.
(b)
Instead of a $20 discount, suppose that WMU students get a 5% discount
on the monthly rent for all 1-bedroom apartments.
The discounted monthly rent for the sample of 1-bedroom apartments
should yield an average of ________________ with SD
________________.
(c)
If you took the 1-bedroom and 2-bedroom samples together, would the SD of
their monthly rents be equal to $100, smaller than $100, or larger than $100?
7.
Golden delicious apples were packed in
plastic bags for delivery. The filled bags averaged 9.5 pounds in weight,
and the SD was .8 pounds.
(a)
The bags of apples are sold to a grocery chain, at a price
of 30 cents per pound. (The heavier bags will, of course, cost more than the
lighter bags.) The price per bag should average __________ dollars
with SD __________ dollars.
(Hint: Price = (Weight)($.30).)
(b)
Suppose that the grocery chain uses their own trucks to pick up the
bagged apples from the grower. For the trucking fee, they charge the grower
25 cents per bag. Therefore for each bag they pay a net price of
(Weight)($.30)-$.25. The net price per bag should average __________ dollars
with SD __________ dollars.
