Study results indicate that the mean length of time people spend on a bus in a city is between 21.2 min and 24.5 min

What is the study margin of the error?

so for this is it 1.65?

See u first need to check which is the most close the given value now you need to choose middle value and hence the margin will be the difference divided by two with a plus and minus sign.

Over here its 26.5-22.4=4.1

Now dividing by 2 we get 2.05

Hence the margin error is ± 2.05

Now add this to 1st number or subtract from the second no. and hence thats the no. from which the no. is deviated 22.4 ± 2.05