Using percentages to help boost basketball performance

Speaker 1: I've been assigned to be your coach. I heard you need some help with your shooting.

Speaker 2: Yeah, I really want to get into the try-outs.

I need to score 65% of my shots.

Speaker 1: We can spend our sessions working that out if you want.

Speaker 2: But at the moment I don't know what my percentage is.

Speaker 1: The way we work this out is we get you to shoot the basketball 30 times and try to find out the average.

Speaker 2: Makes sense to me.

Speaker 1: (TO AUDIENCE) I think the best way to do this is by doing a tally.

Tally charts are used to collect data quickly and efficiently.

Filling in a chart with marks representing numbers is faster than writing out words or figures and the data is collected into subgroups immediately, making it easy to analyse.

Speaker 1: So Justin, how did I do?

Speaker 2: Well I counted that you scored 18 times, that's pretty impressive, but you hit the backboard 9 times and you missed the net 3 times.

We'll count the backboard as a near miss.

You missed 3 times out of 30, as a fraction that is 3 over 30, that's the same as 1 over 10.

That's nice and easy as a decimal, just 0.1.

This means you completely missed 10% of the time.

Speaker 1: Right.

Speaker 2: You hit the backboard 9 times, let's work this out as a fraction.

We must divide 9 by 30, the answer is 0.3.

Now we'll have to times it by 100, which is 30%.

Finally let's figure out what your score rate is, this time I'm gonna divide 18 by 30, this shows 0.6.

So now I'm gonna have to multiply 0.6 by 100 to get the percentage of the actual scores.

So 0.6 times 100 equals 60%.

That's not that good. Shall we just check this quickly?

That 60 plus 30 plus 10 equals 100.

Speaker 1: I scored 60% but I need 65. I'm sure I can improve.

Speaker 1: Let's work out what you need to do to make the team selections.

Speaker 2: That'll be a great help.

Speaker 1: So you need to increase your score rate from 60 to 65 percent.

That's an increase of 5 percent, to make the team.

If you go with the same number of shots as before, we need to work out what 5 percent of 30 is.

A quick way to work out 5 percent is to find out what 10 percent is.

And we know that 10 percent of 30 is 3, but we need to work out what 5 percent is.

If we know that 5 percent is half of 10, and we know that 10 (percent) is 3, we would only have to halve 3, which is 1.5.

Speaker 2: Great, what I need to do is increase my 18 scores out of 30, by 1.5.

But I can't get a score of 1.5, so I will round that to 2.

2 plus 18 equals 20. Alright, so if I make 20 out of 30, I will definitely make the trials?

Speaker 1: Exactly, that's right.

Speaker 2: Let's get to it then.