Question
The mean marks of the following distribution is:Marks Obtained No. of Students 81 15 35 4 73 3 56 16
The correct answer is
65
Given:
Values (x): 81, 35, 73, 56
Frequencies (f): 15, 4, 3, 16
Formula:
Mean = Σ(fx) ÷ Σf
Calculations:
⇒ 81×15 = 1215
⇒ 35×4 = 140
⇒ 73×3 = 219
⇒ 56×16 = 896
⇒ Σfx = 1215 + 140 + 219 + 896 = 2470
⇒ Σf = 15 + 4 + 3 + 16 = 38
⇒ Mean = 2470 ÷ 38 = 65
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Important Questions from Elementary Statistics (Notes)
Let $X_1, X_2, X_3$ be a random sample of size 3 from an absolutely continuous distribution that is symmetric about 0. For $i=1,2,3$, let $R_i$ denote the rank of $|X_i|$ among $|X_1|, |X_2|$ and $|X_3|$.
If $T^+ = \sum_{i=1, X_i>0}^3 R_i$
is the Willcoxon signed-rank statistic, then which of the following statements are true?,
- Which of the following is the first step in calculating the median of data set?
1. Average the middle two values of the data set
2. Array the data
3. Determine the relative weights of the data values in terms of importance
4. Find the average distance of the observations in the data set from the mean - If the median of a data is 61.54 less than its mode, then the median of the data exceeds its mean by _____. (Use the empirical formula to find the answer)
- The geometric mean of 100 observations is 25. If each observation is multiplied by 4, what will be the new geometric mean?
- The sum of deviations of the items from __________ ignoring signs is the least?
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