CS100M
Prelim 1 review questions
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Chapman 3.5,3.6,3.8,4.5,4.6,4.20
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1.  Concepts: I/O, conditionals, mod

Read in the year and print whether it is a leap year using (something
equivalent to) the rules below:
	Rule 1.  A non-multiple of 4 is not a leap year.
	Rule 2.  A multiple of 4 is a leap year.
	Rule 3.  Rule 2 does not apply to multiples of 100.
	Rule 4.  Rule 3 does not apply to multiples of 400.

Hint:	REM and MOD are MATLAB functions for finding the remainder. Use HELP
	to check them out.  E.g., rem(x,y) returns the remainder when x is
	divided by y.
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2.  Concepts: I/O, simple matrix manipulation, array arithmetic, 
	MATLAB functions

Annual US fatality rates (per 100 million vehicle miles) on all roads are
stored in a file called $rates.dat$ as an n-by-3 matrix:
	- column 1 contains the years
	- column 2 contains the actual rates
	- column 3 contains the model predicted rates
For example, a row in the file $rates.dat$ looks like this:
	1978	3.39	3.31

Write a program that performs the following tasks:
	- read the data in the file $rates.dat$
	- store the actual fatality rates as the vector variable $actual$
	- store the model predicted rates as the vector variable $model$
	- for each year, calculate the percent error of the modeled rate.
	  Percent error is  (|actual-model|/actual)*100
	  Store the percent errors in a vector variable $errors$
	- Calculate the average percent error (for all years)

Potentially useful MATLAB functions:
  INPUT, LOAD, SIZE, ABS, SUM, MEAN