Question 917070
I am confused too.
They say 30% of cars are known to have at least 1 underinflated tire. Where?
In the whole world? In your town?
Whatever place they are talking about,
the proportion of the vehicles with at least one underinflated tire there is
{{{30/100=0.30}}} .
So, if we are talking about the fraction of all the cars in that place that have at least one underinflated tire,
that is 0.30, so the probability that 0.30 is less than 0.20 is zero.
Now, if you just look at the first ten cars you see in that place,
or at any subset of all the cars in that place,
the proportion of the vehicles with at least one underinflated tire may be more or less than 0.30. It may be even less than 0.20. So the probability that the proportion of vehicles with at least one underinflated tire is less than .20 is not zero and depends of the subset being examined.