5.1. Arithmetic Mean

Try these first

1. 1.

   What is the arithmetic mean of the following rainfall data: 20mm, 30mm, and 50mm?

   Hint

   Add the numbers then divide by the total count.

2. 2.

   What type of instrument is used to measure rainfall?

   Hint

   Think about what we use to collect water from rain.

3. 3.

   What is the arithmetic mean of 10, 20, and 30?

   • 20
   • 30
   • 10

   Hint

   Remember the formula: Add and Divide.

4. 4.

   True or False: The arithmetic mean is effective for data that is unevenly distributed.

   • True
   • False

   Hint

   Think about how averages can sometimes be misleading.

5. 5.

   Given a region covered by four rain gauges with the following measurements: Gauge A: 30mm, Gauge B: 80mm, Gauge C: 60mm, Gauge D: 135mm with areas influenced at 100, 150, 75, and 200 km² respectively, calculate the weighted mean rainfall using both the Arithmetic Mean and Thiessen Polygon Method.

   Hint

   First, calculate the simple average separately then use the weighted averages for the greater accuracy regarding areas.

6. 6.

   Evaluate how inaccuracies in rainfall measurement might affect agricultural planning decisions, especially concerning drought and flood outcomes.

   Hint

   Think about what farmers might decide based on predicted rainfall and how errors could lead to setbacks.