Introduction to Statistical Reasoning
Instructor: Ivo Dinov, Asst. Prof.
Departments of Statistics & Neurology
Friday, Oct.12, 2001, turn in at the end of lecture
submission rules. On the front page include the following
(HW_2_1) Backpacks are commonly seen in many places, especially
university campuses, schools, shopping malls and airplanes. In 1997, a
US consumer magazine conducted a study on backpacks. Some of the data from
the study is reproduced in the table below. The price of the backpacks
is to the nearest US dollar, volume is measured in cubic inches and number
of books is the number of 5-inch by 7-inch by half-inch books that the
backpack easily holds.
Calculate the average volume used per book (i.e. the volume divided by
the number of books) for each backpack.
Calculate the average the standard deviation of
the backpack price, volume and number of books.
What does the price distribution across manifacturers look like? Bell-shaped?
Symmetric? Unimodal? Try to draw the price histogram using bins of size
5, starting at the mean.
Write a short report (from 150 to 250 words) about the data. Your report
should include a discussion on the data (comments on trends, problems or
interesting features in the data and what other data could be collected
to help consumers compare backpacks) and a recommendation for consumers
(which backpack(s) do you recommend buying and why). Are we missing some
factors that may effect our purchasing decision? If so, give examples.
|Number of Books
(HW_2_2) Describe/Address the following terms in your own words:
Give two examples of each of the three basic ways for data collection (surveys,
designed experiments and observational studies).
\Ivo D. Dinov, Ph.D., Departments of Statistics and Neurology,
UCLA School of Medicine/