Question

the iq scores of 50 students are given below.
112 97 106 98 102 90 107 108 99 93
114 103 104 86 94 91 87 99 108 118
100 114 88 90 88 118 104 110 115 96
108 95 101 104 89 107 119 85 106 103
97 98 106 105 108 117 93 117 114 90
(a) construct a grouped frequency distribution for the data. use 85 - 89 for the first class and use the same width for each subsequent class.
class frequency
85 - 89 5

Explanation:

Step1: Determine class - width

The first class is 85 - 89, so the class - width is \(89 - 85=4\).

Step2: Define subsequent classes

The subsequent classes will be 90 - 94, 95 - 99, 100 - 104, 105 - 109, 110 - 114, 115 - 119.

Step3: Count frequencies

For the class 90 - 94: Count the number of scores in the range. There are 8 scores (94, 91, 90, 90, 93, 90, 93, 90).
For the class 95 - 99: There are 9 scores (97, 98, 99, 99, 95, 97, 98, 96, 99).
For the class 100 - 104: There are 12 scores (102, 103, 104, 100, 104, 101, 104, 103, 104, 100, 103, 104).
For the class 105 - 109: There are 10 scores (106, 107, 108, 108, 105, 106, 107, 108, 106, 108).
For the class 110 - 114: There are 7 scores (114, 114, 110, 115, 114, 114, 110).
For the class 115 - 119: There are 4 scores (118, 118, 119, 117, 117).

Answer:

Class	Frequency
90 - 94	8
95 - 99	9
100 - 104	12
105 - 109	10
110 - 114	7
115 - 119	4