Statistics
NCERT Exemplar Ch 12
CBSE_NCERT_EXEMPLAR_CH12
Grade 10
Question:
In the formula $\bar{x} = a + \dfrac{\sum f_i d_i}{\sum f_i}$, for finding the mean of grouped data, $d_i$ are deviations from $a$ of:
Lower limits of the classes
Upper limits of the classes
Mid-points of the classes
Frequencies of the class marks
Step-by-Step Solution
Key Concept: $d_i = x_i - a$, where $x_i$ is the class mark (mid-point of class).
Stepwise Solution:
$d_i$ represents the deviation of class marks $x_i$ (mid-points) from assumed mean $a$. [1.0 Mark]
Marking Scheme:
• Selecting Mid-points of the classes: 1.0 Mark
Correct Answer: Mid-points of the classes
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