Class boundaries-Frustrating

The durations (in minutes) of 100 phone calls were recorded, resulting in the frequency distribution below.

duration of calls 0- 1- 2- 3- 4- 5- 10- >20

Frequency 7 18 34 25 13 2 1 0.

Does this mean to the nearest minute and so the class boundaries would be 0<= min <0.5, 0.5<=min<1.5 etc

or 0<=min<1,1<=min<2, 2<=min<3 etc. The question is for testing goodness of fit.

Also

Y is distributed as N(50,100). One hundred observations of Y result in the following frequency distribution. Carry out a goodness of fit test at the 2.5% sig level.

observations of Y <30 30- 40- 50- 60- >70

Frequency 3 14 30 35 14 4

I dont know what the real boundaries should be??

29.5>Y, 29.5<=Y<39.5, etc

or something else.

Thanks!