A school wants to put a bond in the next election, they call this bond Measure K.
They select a random sample of voters in the county and find a 90% confidence interval for the proportion of voters in this county who would vote yes.
Recall that a hypothesis test is used when we want to test an assertion or a claim.
For the given case, there is no assertion or any claim so this is definitely not a hypothesis test.
This is in fact a confidence interval since we are interested in the proportion of voters in this county who would vote yes.
The confidence interval would give us a fair estimate of the true population proportion of voters in this county who would vote yes.
Now coming to whether is it a 1 proportion or 2 proportion confidence interval.
Notice that there is only 1 proportion for the given case that is the proportion of voters in this county who would vote yes.
Therefore, the need to use "1 proportion (z) confidence interval"