Use the frequency distribution to determine

(a) The total number of observations.

(b) The width of each class.

(c) The midpoint of the second class.

(d) The modal class (or classes).

(e) The class limits of the next class if an additional class were to be added.

Class . . . . . . . . . . Frequency

40-49. . . . . . . . . . . . . . 7

50-59 . . . . . . . . . . . . .5

60-69. . . . . . . . . . . . . 3

70-79 . . . . . . . . . . . . . 2

80-89 . . . . . . . . . . . . . 7

90-99 . . . . . . . . . . . . . 1