David W. answered • 06/03/21
Q: "On a fishing trip with his father, Alex caught eight bass with a mean mass of 1.2 kg and five trout with a mean mass of 2.9 kg. What was the mean mass, in kilograms, of all the fish that Alex caught?"
Important information:
All units are kilograms.
MEAN is the arithmetic average (i.e., total divided by count)
So, Total is mean*count ( since mean is total divided by count )
The total mass of the eight bass is 8*1,2 kg.
The total mass of the five trout is 5*2.9 kg
The total mass of thirteen fish is 8*1,2 + 5*2.9 kg. That is 24.1 kg.
The mean (average) mass of the 13 fish is 24.1 kg / 13 fish = 1.85 kg per fish
David W.
If you simply add the MEANS you get 4.1 kg/fish, but the values of 1.2kg and 2.9kg MUST BE WEIGHTED. The total mass of the eight bass is 8*1/2 kg. = 12 kg. The mean mass of the eight bass is 12 kg/8 = 1.2 kg per fish The total mass of the five trout is 5*2.9 kg = 14,5 kg The mean mass of the five trout is 14.5 kg/5 = 2,9 kg per fiish Do the math using these numbers. Often, the mean is expressed as just the average value rather than the value per item (fish). For example, mean in kg rather than kg per fish.06/03/21
Gary H.
I understand, but that isn't what I'm asking, I just wanted to know why can't it be divided by 4.1 (sum of category weights) its part of the formula, WEIGHT FORMULA, (sum of(category value x category weight)) divided by sum of category weights. That's my only question, why is it divided by the total fish it doesn't make sense to me.06/03/21