Maths · Measures of dispersion; calculation of mean, median, mode of grouped and ungrouped data
The mean and variance of observations are 5 and 0 respectively. If then is
The mean and variance of \( n \) observations \( x_{1}, x_{2}, x_{3}, \dots \dots \dots \dots . . x_{n} \) are 5 and 0 respectively. If \( \sum_{i=1}^{n} x_{i}^{2}=400, \) then \( n \) is
- A. 10
- B. 20
- C. 25
- D. 36
Step-by-step solution
Given mean = 5 and variance = 0, all observations are equal to 5. Thus, ∑xi² = n × 25 = 400, so n = 16. Since 16 is not among the options, there may be a typo; if ∑xi² were 500, n would be 20.
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