Answer is 30

Q1=mean-0. 675*SD
Q3=mean-0. 675*SD
therefore
Q1=6.755
Q3=3.245
coefficient of quartile deviation=Q3-Q1/Q3+Q1*100
=35.1
ans is 35

Understanding Coefficient of Quartile Deviation
The coefficient of quartile deviation is a measure of relative dispersion that indicates the spread of the data in relation to the quartiles. It is calculated using the formula:
Coefficient of Quartile Deviation = (Q3 - Q1) / (Q3 + Q1)
Where:
- Q1 = First quartile
- Q3 = Third quartile
Given Values
- Mean = 5
- Standard Deviation = 2.6
- Median = 5
- Quartile Deviation = 1.5
Calculating Quartiles
To find the coefficient of quartile deviation, we need to derive Q1 and Q3 using the quartile deviation:
- Quartile Deviation = (Q3 - Q1) / 2
- Rearranging gives us:
- Q3 - Q1 = 2 * Quartile Deviation
- Q3 - Q1 = 2 * 1.5 = 3
You can express Q3 in terms of Q1:
- Q3 = Q1 + 3
Finding Coefficient of Quartile Deviation
To compute the coefficient, note that we need both Q1 and Q3 values. Since we don't have specific values for Q1 and Q3, we can express the coefficient using the relationship derived above:
- Coefficient of Quartile Deviation = (Q3 - Q1) / (Q3 + Q1) = 3 / (Q1 + Q1 + 3) = 3 / (2Q1 + 3)
However, the exact coefficient cannot be determined without the values of Q1 or Q3.
Conclusion
The coefficient of quartile deviation is a useful statistic for understanding data dispersion. While we have derived the relationships, specific quartile values are needed for calculation.