The theoretical probability of the coin landing heads up is 0.5.
Given that,
Isla flipped a coin 30 times.
The coin landed heads up 9 times and tails up 21 times.
We have to determine,
What is the theoretical probability of the coin landing heads up?
According to the question,
By using the theoretical probability concept assuming it means a percentage, so to turn a fraction into a percentage the top by the bottom (9÷30) and multiply by 100.
[tex]=\dfrac{9}{30}\times 100\\\\= 90 \ percent[/tex]
And, to turn a fraction into a percentage the top by the bottom (9÷30) and multiply by 100.
[tex]= \dfrac{9}{21} \times 100\\\\= 42.86 \ percent[/tex]
It depends on if it wants a basic probability on how many times it will land on heads, if it does use 42.86%. If it wants a probability out of 30 it's 30%.
Therefore,
The theoretical probability of the coin landing heads up is given by,
[tex]=\dfrac{50}{100}\\\\= \dfrac{1}{2}\\\\= 0.5[/tex]
Hence, The theoretical probability of the coin landing heads up is 0.5.
To know more about Probability click the link given below.
https://brainly.com/question/23044118
