Data Exploration: Employee Salaries

Learning Outcomes

• Compare the characteristics of two data sets graphically

Salary data from two companies is presented below, Company A and Company B, both in the same field and geographic region. We want to compare the salaries by looking at graphical representations of the data.

Salaried Employees: Company A

 68340 87282 103802 128863 140085 162300 177109 70138 90553 106562 128933 147419 168676 180174 71417 95226 120701 130780 149514 169409 180221 71867 97042 123313 136204 152008 170031 185837 84675 100531 125614 138920 155032 175118 189320

Salaried Employees: Company B

 35472 43467 53624 65096 72290 110351 124732 36983 46652 57946 66235 75279 117574 228920 38382 49655 59096 69721 107368 118810 245427 41674 53231 59709 71289 108236 119112 275024 43256 53506 61724 72211 109472 124678 293012

Step 1: Store the data

1. Type or copy the data into a new spreadsheet. Title the tab Employee Salaries. Place the columns of data side by side in column A and column B.
2. Obtain descriptive statistics for each company’s data.
3. Analyze the descriptive statistics and compare the companies’ data.

Step 2: Create a box and whisker plot with both data series on the same graph

1. Select both columns of data together with their labels.
2. Click on Insert then Box and Whisker. You should see both sets of data appear as parallel box plots on the graph in different colors. Click to select it.
3. Click the plus sign next to the chart. Click to select Legend. The data column labels should appear at the top under the Chart Title. You can now delete the Chart Title.

Step 3. Create a scatter plot with both data series on the same graph

1. Follow the same steps as in Step 2 above, except this time choose Scatter Plot instead of Box and Whiskers.

Step 4: Analyze the data

As we saw in the descriptive statistics, Company A has a tighter distribution of salaries about its center. Company B possesses extremes at both ends of salary range. The salaries in B are persistently and substantially lower than A’s are with the notable exception of four outliers at the top end. These are pulling the mean of B far to the right of the median. With B’s median salary at $69,721 and A’s at$130,780, it is clear that the salary distribution at company A is more equitable than at company B. A has the higher starting salary, and higher salaries overall than all but the four outliers at company B.