Consider the following statements:

(i) The classes of type 15 - 19, 20 - 24, 25 - 29 etc. are exclusive classes.

(ii) The classes of type 15 - 20, 20 - 25, 25 - 30 etc. are inclusive classes

Which of the above statements is/are correct?

1. (i) only

2. (ii) only

3. Both (i) and (ii)

4. Neither (i) nor (ii)

The class-mark of a class interval is 42. If the class-size is 10, then the upper and lower limits of the class are

1. 47 and 37

2. 47.5 and 37.5

3. 46.5 and 36.5

4. 46 and 36

The width of each of nine classes in a frequency distribution is 2.5 and the lower class boundary of the lowest class is 10.6. Which of the following is the upper class boundary of the highest class?

1. 28.1

2. 30.6

3. 33.1

4. 35.6