This question is on my study guide for the final. It’s simple but I’m not very clear:
In order to determine the mean weight of bags of chips filled by its packing machines, a company inspects 50 bags per day and weighs them. In this example what is the population?
Are they looking for a number or a raw answer such as “The bags” or a figure such as “The weight of the chips?”
They’re looking for what you call a raw answer which wonl’t have a number in it actually.
The population is all the bags of chips that the company produced that day.
There is a prohibition on the boards against doing someone’s homework for them. The OP was laudable in getting help understanding the <i>question</i> rather than asking for the answer, and <b>OldGuy</b> was equally laudable in answering the question about the question. Caution in the future.
Unless they’ve changed the rules just recently, the prohibition is against asking other people to do your homework. Giving the answer to a question asked has never been forbidden.
A population isn’t a number; it’s a set: the set of all people or things you’re considering. If the company wants to know the mean weight of bags of chips filled by its packing machines, the set of all bags of chips filled by its machines is the population, and what they want to know about it is the mean weight.
The 50 bags a day that they actually weigh constitute a sample of this population: a subset which is supposed to represent the whole population. If the sample selection was done in a valid way, there shouldn’t be anything special about the bags they actually weighed compared to all the others they didn’t weigh, and they can be pretty sure that the mean weight of the bags in their sample is pretty close to the mean weight of all the bags in the population (since would be impossible, unfeasible, or just more trouble than it’s worth to weigh every single bag in the whole population).
This business of “population” and “sample” is arguably the single most important concept in statistics.
have you covered venn diagrams? I’m thinking they might help tie up some loose ends and give you the answer. For example, a question with sample size, population, etc given as a multi - step problem.