Mean of following frequency distribution is \(9.3\) then \(\mathrm{K}\) is $$ \begin{array}{|l|l|l|l|l|l|l|} \hline \mathrm{Xi} & 4 & 6 & 7 & \mathrm{~K} & 12 & 14 \\ \hline \mathrm{Fi} & 5 & 6 & 8 & 10 & 2 & 9 \\ \hline \end{array} $$ (a) 11 (b) 12 (c) 10 (d) 13

Short Answer

Expert verified
The value of K is 11, making the correct option (a) 11.

Step by step solution

01

Write down the given information

The frequency distribution table and mean provided are: $$ \begin{array}{|l|l|l|l|l|l|l|} \hline \mathrm{Xi} & 4 & 6 & 7 & \mathrm{~K} & 12 & 14 \\\ \hline \mathrm{Fi} & 5 & 6 & 8 & 10 & 2 & 9 \\\ \hline \end{array} $$ Mean: \(9.3\)
02

Recall the formula for calculating the mean

The formula for calculating the mean of a frequency distribution is: Mean = \(\frac{\sum (Xi \cdot Fi)}{\sum Fi}\)
03

Substitute the given information into the formula and solve for K

Plug the given information into the formula and set it equal to the mean (9.3): \(9.3 = \frac{(4 \cdot 5) + (6 \cdot 6) + (7 \cdot 8) + (K \cdot 10) + (12 \cdot 2) + (14 \cdot 9)}{5 + 6 + 8 + 10 + 2 + 9}\) Solve for K: \(9.3 \times (5 + 6 + 8 + 10 + 2 + 9) = (4 \cdot 5) + (6 \cdot 6) + (7 \cdot 8) + (K \cdot 10) + (12 \cdot 2) + (14 \cdot 9)\) Calculate the sum of the frequencies: \(9.3 \times 40 = (20) + (36) + (56) + (10K) + (24) + (126)\) Multiply the mean by the sum of the frequency: \(372 = (20) + (36) + (56) + (10K) + (24) + (126)\) Combine like terms and solve for K: \(372 - (20 + 36 + 56 + 24 + 126) = 10K\) \(110 = 10K\) Divide both sides by 10: \(K = 11\)
04

State the final answer

The value of K is 11, making the correct option (a) 11.

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