\[{{x}_{i}}\] | 140 | 145 | 150 | 155 | 160 | 165 | 170 | 175 |
\[{{f}_{i}}\] | 4 | 6 | 15 | 30 | 36 | 24 | 8 | 2 |
A) 8.64
B) 7.26
C) 7.05
D) None
Correct Answer: B
Solution :
Let us assume an arbitrary mean a = 155. Following table is constructed :\[{{\text{X}}_{\text{i}}}\] | \[{{\text{f}}_{\text{i}}}\] | \[{{u}_{\text{i}}}=\frac{{{X}_{i}}-155}{5}\] | \[u_{i}^{2}\] | \[{{f}_{i}}{{u}_{i}}\] | \[{{f}_{i}}u_{i}^{2}\] |
140 | 4 | -3 | 9 | -12 | 36 |
145 | 6 | -2 | 4 | -12 | 24 |
150 | 15 | -1 | 1 | -15 | 15 |
155 | 30 | 0 | 0 | 0 | 0 |
160 | 36 | 1 | 1 | 36 | 36 |
165 | 24 | 2 | 4 | 48 | 96 |
170 | 8 | 3 | 9 | 24 | 72 |
175 | 2 | 4 | 16 | 8 | 32 |
Total | 125 | 77 | 311 |
You need to login to perform this action.
You will be redirected in
3 sec