Math Is Fun Forum

Lydia_g

Guest

Maths

Hi, help with this question please!

A pupil wants to investigate a report that Belgian one euro coins are biased in favour of heads.
Here is her plan for the investigation:

I will spin 20 Belgian one euro coins to give one set of results. I will do this ten 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 10 sets of results:
10 13 11 11 12 12 11 9 10 11

Using the pupils plan, what should her conclusion be?
You must show your working.

Thankyou !

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: Maths

hi Lydia_g

Welcome to the forum.

Normally, to test for bias, we would assume no bias, using P = 0.5, and then calculate how unlikely those results are.

But the pupil has told you how to determine the bias.  Just calculate the probability from the results.

There are 20 spins repeated 10 times so that makes 200 spins altogether.  Calculate the total number of heads, divide by 200, and change to a percentage.  If it's over 56%, you are to declare the coins are biased.  If it's 56% or under you should say there is no evidence of bias (rather than say the coins are unbiased).

Bob

ps.  What exam level did this come from?

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob