Question

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

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 50-69 5 70-89 23 90-109 19 110-129 11 130-149 1

b)

class width = 70-50 = 20

c)

class mid point = (lower limit+upper limit)/2

 class frequency mid point 50-69 5 60 70-89 23 80 90-109 19 100 110-129 11 120 130-149 1 140

d)

 class frequency mid point cumulative frequenncy 50-69 5 60 5 70-89 23 80 28 90-109 19 100 47 110-129 11 120 58 130-149 1 140 59

N/2 = 59/2 = 29.5

so, median containing class is (90-109)

e)

 class frequency,f mid point,X cumulative frequenncy X*F 50-69 5 60 5 300 70-89 23 80 28 1840 90-109 19 100 47 1900 110-129 11 120 58 1320 130-149 1 140 59 140 total 59 5500

mean=ΣXF/Σf = 5500/59=93.22