Math Is Fun Forum

atut

Member

Registered: 2008-04-23

Posts: 30

Key Stage Three Math

A pupil wants to investigate a report that Begian one euro coins are biased in favour of heads.

Here is the plan for the investigation:

I will spin 20 Belgian one euro coins to give one set of results. I will do this 10 times to give a total of 200 results to work out an estimated probability of spinning a head. If this probability is greater than 56% my conclusion will be that Belgian one euro coins are biased in favour of heads.

The table shows the ten sets of results:

Number of each set of 20 coins than showed heads.

10  13  11      11  12 12 11 9 10   

Using the pupils plan, what should her conclusion be?

You must show your working plzz

Thanks Bye

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Key Stage Three Math

You have 9 results and a gap there, so it looks like you might have missed one.

If we take these results as complete, then adding them up shows that heads came up 99 times out of 180. This gives an estimate probability of 99/180 = 0.55 = 55%, so according to the condition, the Euro should be assumed as unbiased.

But as I said, it looks like you've missed one of the results so you might need to use the above method with that missing number incorporated.
(Or cheat - the Euros are biased if the missing result is 14 or more. )

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Why did the vector cross the road?
It wanted to be normal.