Iam stuck on this question of knowing how to break it down to get the answer

Type the correct answer in each box. spell all the words correctly, and use numerals instead of words for numbers. if necessary, use / for the fraction bar(s).

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?

How many and of which kind of roots does the equation f(x)=2x^4−9x^3+17x^2−16x+6 have?