% IAP 2007 Introduction to MATLAB: Interface and Basics
% Instructor: Violeta Ivanova, violeta@mit.edu

% EXAMPLE 1 Massachusetts Census Data
% Data import & export, variables, vectors, operators, built-in functions.

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% A. DATA I/O

% A1. Import census data using the Import Wizard
% Load the numerical data from file MA2000census.dat into a matrix called N.
% Hint: import only the numerical 14x9 matrix data after changing its name.

% A2. Display the elements of the matrix N


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% B. VECTORS & MATRICES

% B1. Create a vector Area of county areas from matrix N:


% B2. Create vectors M and F with county populations by gender:



% B3. Create a vector P with total county populations:


% B4. Create a matrix G with county populations of both genders: males in one
% column, and females in the second collumn.

% From the matrix N:


% From the two vectors M and F:


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% C. MATRIX OPERATIONS

% C1. Addition: From the vectors M and F, create a vector All with total number
% of people in each county.



% C2. Division: Create a column vector Ppa with population density (number of people 
% per area) for each county. Note: you must use the . operator!



% C3. Create a 14x2 matrix Pct with percents of males (one column) and females 
% (another column) for each county. Note: you must use the . operator! 



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% D. VARIABLES

% Test what variables have been created so far with functions WHO or WHOS:


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% E. BUILT-IN FUNCTIONS

% E1. Function SUM: Compute the total number MAall of residents in MA. 


% E2. Function MEAN and STD: Compute the mean and standard deviation 
% of the numbers of males and the numbers of females in MA counties.




% E3. Function SAVE: Export the percentile matrix Pct to a text file.


% E4. Function LOAD: Import the saved data from the file into a matrix Percents.