Calculating the standard deviation from a frequency table.

Find the standard deviation of the data in the given frequency table. A company had 80 employees whose salaries are summarized in the frequency table below. Find the standard deviation. Salary / Employees 5001-10000 / 17 10001-15000 / 16 15001-20000 / 20 20001-25000 /15 25001-30000 /12

Solving system of equations: Supply and Demand Equations

Solve the following system of equations that model supply and demand for a product: p - q = 0 ( supply equation ) cp - q = -1 ( demand equation ) where p = price and q = quantity Solve first when c = 0.999 and a second time when c = 1.001. What does the difference in solutions suggest about the importance of having highly accurate coefficients in the system? Remembering that this is a model of supply and demand, are there any solutions that can be tossed out? Why?

Matrices

What must be true about x,y,z,w, if we require AB = BA for the matrices A= [x y] and B= [ 1 1] [z w] [-1 1]

Simplex Method

Maximize P = 100x1 + 200x2 + 50x3 Subject to the constraints 5x1 + 5x2 + 10x3 < = 1000 10x1 + 8x2 + 5x3 < = 2000 10x1 + 5x2 < = 500 x1 > = 0 x2 > = 0 x3 > = 0

Working with the simplex method.

Maximize P= 40x1 + 60x2 + 50x3 Subject to the constraints 2x1 + 2x2 + x3 < = 8 x1 - 4x2 +3x3 < = 12 x1 > = 0 x2 > = 0 x3 > = 0