The following data represent trunk circumferences in mm for

The following data represent trunk circumferences (in mm) for a random sample of 60 four-year-old apple trees at East Malling Agriculture Research Station in England (Reference: S. C. Pearce, University of Kent at Canterbury).
108 99 106 102 115 120 120 117 122 142
106 111 119 109 125 108 116 105 117 123
103 114 101 99 112 120 108 91 115 109
114 105 99 122 106 113 114 75 96 124
91 102 108 110 83 90 69 117 84 142
122 113 105 112 117 122 129 100 138 117

(a) Make a frequency table with seven classes showing limits, class boundaries, midpoints, frequencies, and relative frequencies. (Give relative frequencies to 2 decimal places.)
Class Limits Class Boundaries Midpoint Frequency RelativeFrequency CumulativeFrequency
  

_
_
_
_
_
  
(b) Draw a histogram.

(c) Make a relative-frequency histogram.

(d) Identify the shape of the distribution.
skewed left
skewed right
bimodal
uniform

(e) Draw an ogive. (Graph each point and the closed line segments connecting the points to create your graph.)

Solution

Minimum 69 and maximum = 142

Hence range = 73

Let us make 7 classes of 11 width each.

Ascending order.

69, 75, 83, 84, 90, 91, 91, 96, 99, 99, 99, 100, 101, 102, 102, 103, 105, 105, 105, 106, 106, 106, 108, 108, 108, 108, 109, 109, 110, 111, 112, 112, 113, 113, 114, 114, 114, 115, 115, 116, 117, 117, 117, 117, 117, 119, 120, 120, 120, 122, 122, 122, 122, 123, 124, 125, 129, 138, 142, 142

Frequency distribution and relative frequency is shown above.

Frequency polygon will be

It is skewed left