3.2 Exercise:Economic Order Quantity Model: \(Q= \sqrt{2DK/h}\)

- D=5000: annual demand quantity
- K=$4: fixed cost per order
- h=$0.5: holding cost per unit
Q=?

3.3 Exercise:

Define a vector with values (5, 2, 11, 19, 3, -9, 8, 20, 1). Calculate the sum, mean, and standard deviation.

Re-order the vector from largest to smallest, and make it a new vector.

Convert the vector to a 3*3 matrix ordered by column. What is the sum of first column? What is the number in column 2 row 3? What is the column sum?

Use the following code to load the CustomerData to your R.

`customer <- read.csv(file = "https://xiaoruizhu.github.io/Data-Mining-R/lecture/data/CustomerData.csv")`

- How many rows and columns are there?
- Extract all variable names.
- What is the average “Debt to Income Ratio”?
- What is the proportion of “Married” customers?