Engr 160 Homework Assignment

Engr 160 Homework Assignment

Due: Thursday, Nov. 4

The purpose of this program is to use the method of least squares (linear regression) to calculate the m, b and r values for a given set of data points. The given data represents information about the volume of water through a culvert, as a function of the height of the water in the culvert.

Program requirements:

-  Use a main program and a Subroutine subprogram.

-  In the main program, read from the given file (LeastSqrs.txt): on line 1 of the file, read a number which equals the number of data pairs, n (n will never be more than 100); then starting on line 2 of the file the data pairs are listed, (x, y), one per line. Read the data pairs into one-dimensional arrays (one array will contain the x values and the other the y values).

-  In the main program, ask the user if they want you to calculate the regression equation for a linear, exponential or power situation.

-  Based on the users’ response, calculate and send to the Subroutine the correct form of the x and y values (you may need Lny, etc.).

-  In the main program, output to the screen the m, b and r values that are returned from the Subroutine, with the m and b values displayed in the form of the correct general equation (Linear, Exponential or Power).

-  Use only ONE Subroutine to calculate the m, b and r values using the Method of Least Squares to do Linear Regression (equations on back of sheet).

-  In the main program output the Linear, Exponential or Power equation with the calculated values of m and b inserted in the equations. Also output the r values.

Presentation requirements:

-  Create a Word document as the complete solution.

-  No complete write-up required – Solution ONLY

-  In the Solution include: flowcharts, copy of the computer code, a copy of your output (MsgBoxes) and a Command Button to use to run the program.

-  Run your program for all three cases; analyze the output values and determine whether a linear, exponential or power equation best fits the data. In the write-up, clearly indicate which is better and why.

-  Two flowcharts will be needed (one for the main program and one for the subprogram).

Submission requirements:

-  Submit your Word document electronically to the folder for your section.

-  Name your Word file as follows: Number_LastName_FirstName LeastSqrs.docm

-  Submit a printout of your Word file in class on the due date.

Notes about the LeastSqrs.txt input file:

-  On line one, read the value of n (the count of data pair in the file).

-  Starting on line two, the data is given as X, Y

Linear Regression:

Exponential Regression:

x values = x

y values = Ln(y)

b = Ln(b)

Power Regression:

x values = Ln(x)

y values = Ln(y)

b = Ln(b)