Given the chart
Frequency Distribution of
IQ Scores of Low Lead Group
IQ Scores
Frequency
50

69
5
70

89
23
90

109
19
110

129
11
130

149
1
a.
Construct a Histogram
b.
Determine the Class Width
c.
Determine the Class Midpoint
d.
Find the class that contains the Median
e.
Use the Midpoint for each class to calculate the Mean
a)
class  frequency 
5069  5 
7089  23 
90109  19 
110129  11 
130149  1 
b)
class width = 7050 = 20
c)
class mid point = (lower limit+upper limit)/2
class  frequency  mid point 
5069  5  60 
7089  23  80 
90109  19  100 
110129  11  120 
130149  1  140 
d)
class  frequency  mid point  cumulative frequenncy 
5069  5  60  5 
7089  23  80  28 
90109  19  100  47 
110129  11  120  58 
130149  1  140  59 
N/2 = 59/2 = 29.5
so, median containing class is (90109)
e)
class  frequency,f  mid point,X  cumulative frequenncy  X*F 
5069  5  60  5  300 
7089  23  80  28  1840 
90109  19  100  47  1900 
110129  11  120  58  1320 
130149  1  140  59  140 
total  59  5500 
mean=ΣXF/Σf = 5500/59=93.22
Get Answers For Free
Most questions answered within 1 hours.