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Statement-1 :{:(x:,5,6,7,8,9),(y:,4,6,12...

Statement-1 :`{:(x:,5,6,7,8,9),(y:,4,6,12,-,8):}` for given data mean of `x(barx)` is found to be `7.3`. The missing frequency is `10`
Statement-2: In case of a frequency distribution , `barx=(Sigmaf_ix_i)/(Sigmax_i)`

A

a) Both statement I and statement II are correct. Statement II is correct explanation of statement I

B

b) Both statement I and statement II are correct. Statement II is not the correct explanation of statement I

C

c) Statement I is correct and statement II is incorrect.

D

d) Statement I is incorrect and statement II is correct.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will analyze the given data and apply the formula for the mean of a frequency distribution. ### Step 1: Understand the Given Data We have two sets of data: - \( x_i = \{5, 6, 7, 8, 9\} \) - \( f_i = \{4, 6, 12, c, 8\} \) (where \( c \) is the missing frequency) We are given that the mean \( \bar{x} \) is \( 7.3 \). ### Step 2: Write the Formula for Mean The formula for the mean of a frequency distribution is: \[ \bar{x} = \frac{\Sigma f_i x_i}{\Sigma f_i} \] Where: - \( \Sigma f_i x_i \) is the sum of the product of frequencies and their corresponding values. - \( \Sigma f_i \) is the total frequency. ### Step 3: Calculate \( \Sigma f_i x_i \) We will calculate \( \Sigma f_i x_i \) using the given values: \[ \Sigma f_i x_i = (5 \times 4) + (6 \times 6) + (7 \times 12) + (8 \times c) + (9 \times 8) \] Calculating each term: - \( 5 \times 4 = 20 \) - \( 6 \times 6 = 36 \) - \( 7 \times 12 = 84 \) - \( 8 \times c = 8c \) - \( 9 \times 8 = 72 \) So, \[ \Sigma f_i x_i = 20 + 36 + 84 + 8c + 72 = 212 + 8c \] ### Step 4: Calculate \( \Sigma f_i \) Now, we calculate \( \Sigma f_i \): \[ \Sigma f_i = 4 + 6 + 12 + c + 8 = 30 + c \] ### Step 5: Set Up the Equation Using the mean formula: \[ 7.3 = \frac{212 + 8c}{30 + c} \] ### Step 6: Cross-Multiply to Solve for \( c \) Cross-multiplying gives: \[ 7.3(30 + c) = 212 + 8c \] Expanding the left side: \[ 219 + 7.3c = 212 + 8c \] ### Step 7: Rearranging the Equation Rearranging the equation to isolate \( c \): \[ 219 - 212 = 8c - 7.3c \] \[ 7 = 0.7c \] ### Step 8: Solve for \( c \) Now, divide both sides by \( 0.7 \): \[ c = \frac{7}{0.7} = 10 \] ### Conclusion The missing frequency \( c \) is \( 10 \), confirming that Statement 1 is correct. ### Step 9: Verify Statement 2 Statement 2 states that the mean formula is: \[ \bar{x} = \frac{\Sigma f_i x_i}{\Sigma x_i} \] This is incorrect because it should be \( \Sigma f_i \) in the denominator, not \( \Sigma x_i \). ### Final Answer Thus, the correct option is: **Option C: Statement 1 is correct and Statement 2 is incorrect.**
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