Mathematics · Quantitative Aptitude
Statistics and Dispersion
515 Questions
Statistics and dispersion involve the calculation of mean, standard deviation, variance, and coefficient of variation for data sets. These questions also cover probability distributions and cumulative frequency analysis. Such quantitative aptitude topics are heavily featured in banking and SSC examinations.
Standard deviationNormal distributionMean calculationCumulative frequencyCoefficient of variation
Statistics and Dispersion Questions
A
Correct answer
Explanation
The average of four numbers is 9, so their sum is 4 × 9 = 36. Three numbers are given: 5 + 9 + 12 = 26. The fourth number is 36 - 26 = 10. Option A is correct.
D
Correct answer
Explanation
The median is the middle value when numbers are arranged in order. The sequence 16, 18, 20, 22, 24, 26, 28 has 7 numbers, so the 4th number (22) is the median. Option C (23) would be the average of 20 and 24, which is incorrect.
A
Correct answer
Explanation
IQ scores are standardized so that the average (mean) score for a population is always 100, with a standard deviation of typically 15. This is a fundamental property of IQ testing - by definition, 100 represents average intelligence for the reference population. Scores above or below 100 indicate above or below average performance.
A
Correct answer
Explanation
In Microsoft Excel, pressing F11 instantly creates a default chart using the data in the selected range and places it on a separate chart sheet. This is a quick way to visualize data. F12 opens the Save As dialog, F10 activates the menu bar, and F9 recalculates formulas in workbooks set to manual calculation.
D
Correct answer
Explanation
To have an average of zero, the sum of the 20 numbers must be zero. To maximize the count of positive numbers, 19 numbers can be positive (e.g., all 1s), and the 20th number can be a large negative number (e.g., -19) to balance the sum to zero.
D
Correct answer
Explanation
The average of first n natural numbers is (n + 1)/2. For n = 40: (40 + 1)/2 = 41/2 = 20.5. This formula comes from the arithmetic series sum n(n+1)/2 divided by n.
A
Correct answer
Explanation
To keep the average of 20 numbers at zero, the sum must be zero. You can have 19 positive numbers as long as the 20th number is a negative value equal to the sum of the others. You cannot have 20 positive numbers because their sum would exceed zero.
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Poverty
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Line
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Average
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Triangle
C
Correct answer
Explanation
In Hindi, 'Ausat' means average - the typical or central value in a set of numbers. It comes from the mathematical concept of arithmetic mean used in statistics.
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0 to 1
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0 to 10
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0 and infinity
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0 to 100
A
Correct answer
Explanation
The rand function generates uniformly distributed random numbers between 0 and 1 (excluding 0, including 1 in some implementations). Options B, C, and D are incorrect - rand does not generate values from 0 to 10, 0 to infinity, or 0 to 100 by default.
A
Correct answer
Explanation
Let x be the number to add. New average = (6 + 16 + 8 + x)/4 = 13. Therefore: 30 + x = 52, so x = 22. Adding 22 to the sum of 30 gives 52, which divided by 4 equals 13. This is a basic average problem - find the missing value that achieves a target mean.
A
Correct answer
Explanation
In Teradata, all table rows are distributed across every AMP in the system. The Primary Index hash determines which AMP gets each row, but the distribution is always across all available AMPs. This fundamental parallelism enables Teradata's scalability.
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Additive Fact
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Semi Additive Fact
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Non Additve Fact
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None of the above
B
Correct answer
Explanation
Semi-additive facts can be aggregated along some dimensions but not all. 'Average count of orders' is semi-additive because while you can compute averages across time periods, orders themselves are discrete events - you cannot meaningfully 'sum' order counts across time dimensions (adding yesterday's orders to today's doesn't produce a useful business metric). Additive facts (like revenue) can be summed across all dimensions; non-additive facts (like ratios) cannot be summed at all.
B
Correct answer
Explanation
The 'firstobs=50 obs=450' option tells SAS to start reading at observation 50 and stop at observation 450. The number of observations processed is (450 - 50) + 1 = 401.
B
Correct answer
Explanation
The 'firstobs=50 obs=450' option tells SAS to start reading at observation 50 and stop at observation 450. The number of observations processed is (450 - 50) + 1 = 401.
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DVAR
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DSTDEV
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DSTDEVP
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DAVERAGE
C
Correct answer
Explanation
DSTDEVP is the Excel database function that calculates standard deviation based on the entire population of selected database entries. The 'P' suffix indicates population rather than sample. DVAR calculates variance, not standard deviation.