Define the following terms:
(i) Observations
(ii) Raw data
(iii) Frequency of an observation
(iv) Frequency distribution
(v) Discrete frequency distribution
(vi) Grouped frequency distribution
(vii) Class-interval
(viii) Class-size
(ix) Class limits
(x) True class limits

(i) Observation is the value at a particular period of a particular variable.
(ii) Raw data is the data collected in its original form.
(iii) Frequency of an observation is the number of times a certain value or a class of values occurs.
(iv) Frequency distribution is the organisation of raw data in table form with classes and frequencies.
(v) Discrete frequency distribution is a frequency distribution where sufficiently great numbers are grouped into one class.
(vi) Grouped frequency distribution is a frequency distribution where several numbers are grouped into one class.
(vii) Class interval is the width of such a class.
(viii) Class size is the difference between the upper and the lower values of a class.
(ix) Class limits are the smallest and the largest observations (data, events, etc.) in a class.
(x) True class limits are the actual class limits of a class.