Can someone please help me with this

6. The means of five Data Management classes are: 69, 72, 66, 75, and 78. The respective class sizes are: 26, 33, 25, 35, and 37. How would you determine the overall mean for the Data Management course? Is this a regular average {mean}? Is it weighted? Explain your answer and determine the average for all 5 Data Management classes. [5 marks}