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Statistics - Previous Year Questions

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🔍
📅 Year 2024
Q1
CBSE Board Exam 20243 Marks
Find the mean and variance of the first 10 natural numbers.
▶ Show Detailed Solution
Mean = (1 + 2 + … + 10)/10 = 55/10 = 5.5.
Σx² = 10×11×21/6 = 385.
Variance = Σx²/n − (mean)² = 385/10 − 30.25 = 38.5 − 30.25 = 8.25.
📅 Year 2023
Q1
CBSE Board Exam 20234 Marks
Find the mean deviation about the mean for the data 2, 4, 6, 8, 10, 12, 14, 16, 18, 20.
▶ Show Detailed Solution
Mean = (2+4+…+20)/10 = 110/10 = 11.
Deviations |x − 11|: 9, 7, 5, 3, 1, 1, 3, 5, 7, 9; sum = 50.
Mean deviation = 50/10 = 5.