Classifying outcomes using likelihood terms
About this video
Mr. Sanchez picks one notebook at random from 40 notebooks: 4 green and 36 blue. The video sorts outcomes as likely (blue), certain (any notebook), unlikely (green) and impossible (red), and explains that impossible events are not called unlikely.
You'll be able to
- describe an outcome as impossible, unlikely, likely or certain.
- use the numbers in a situation to decide how likely an outcome is.
- explain the difference between unlikely and impossible.
Key words
- certain
- Sure to happen; a 100% chance.
- likely
- Expected to happen most of the time.
- unlikely
- Possible, but expected to happen only rarely.
- impossible
- Cannot happen at all; a 0% chance.
- randomly
- Chosen by chance, with no way of predicting which one.
Transcript
- [Instructor] We're told that Mr. Sanchez is handing out notebooks to students. He has 40 notebooks on a shelf, four green and 36 blue. Mr. Sanchez randomly selects one notebook from the shelf. Which outcome describes something that is unlikely to happen? So pause this video, have a go at that.
All right, now let's look at these choices. So Mr. Sanchez selects a blue notebook. Is this unlikely? Well, 36 out of the 40 notebooks are blue. So this isn't unlikely, this is actually likely. Most of the notebooks are blue out of the 40. In fact, almost all of them, there's only four that are green.
So this one's actually a likely outcome, not unlikely. Mr. Sanchez selects a notebook. Well, this is certain. We're just assuming something horrible doesn't happen to Mr. Sanchez between, well, we, when he decides to select a notebook and actually selects it. Actually, it tells us that he actually selects a notebook.
So he was fine and he was actually able to select a notebook. So this definitely happened. 100% chance, certain. See, Mr. Sanchez selects a green notebook. Well, this is possible, but most of them are not green. So this, I would say, is unlikely. Only four out of the 40 notebooks are green, so it's possible, but it's unlikely.
Mr. Sanchez selects a red notebook. Well, based on what they told us, none of the red, none of the notebooks are red. So this one is impossible. I wouldn't say something that is impossible, I would not call it unlikely. In order for it to be unlikely, you should think that it's plausible.
It could actually happen. So this one's impossible. So I like my choice C.
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