Find the median and mode of the data set: 4, 7, 9, 7, 12, 5, 7.

Step 1: Arrange the data in ascending order.

The original data are:
4, 7, 9, 7, 12, 5, 7

In ascending order:
4, 5, 7, 7, 7, 9, 12

Step 2: Find the median.

There are 7 values, so the median is the middle, or fourth, value.

The fourth value is 7.

Therefore, the median is 7.

Step 3: Find the mode.

The mode is the value that occurs most frequently.

The value 7 occurs three times, more than any other value.

Therefore, the mode is 7.