Mathematics ยท 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

Multiple choice technology programming languages

Data X; do i = 1 to 10; i = i*3; output; end; output; Run; How many observations will be there in Dataset X and what will be the value of I at last Observation?

  1. No. of Observations = 2 I = 12

  2. No. of Observations = 10 I = 30

  3. No. of Observations = 4 I = 12

  4. No. of Observations = 3 I = 13
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The DO loop starts at i=1. Inside, i=i*3 makes i=3 on first iteration. After OUTPUT and END, loop checks i <= 10. Next iteration i becomes 6 (3*3), then 9 (6*3 would be 18 > 10, so only 3 iterations). Final OUTPUT after loop is 4th observation. Final i=9+3=12 (from last multiplication) + 1 from loop increment.

Multiple choice technology programming languages

data sw; input name $ gender ; datalines; bary 0 bary 0 celina 1 ; run; data re; input name $ gender salary ; datalines; bary . 45000 celina 1 40000 ; run; data final; merge sw re; by name; run; How many Observations will be there in dataset final and what would be the minimum value of gender variable

  1. Observations = 2 and Gender = .

  2. Observations = 2 and Gender = 0

  3. Observations = 3 and Gender = 0

  4. Observations = 3 and Gender = .
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice technology programming languages

Dataset x Rev1 Rev2 Rev3 Rev4 1 3 4 5 data y; set x; z=mean(?); run; Fill in the mean function call.

  1. mean(Rev1-Rev4)

  2. mean(of Rev:)

  3. mean(Rev1 Rev2 Rev3 Rev4)

  4. mean(of Rev1,Rev2,Rev3,Rev3)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mean(of Rev:) syntax uses the SAS variable list shortcut 'of Rev:' which refers to all variables starting with 'Rev'. This is the most concise and correct way to calculate the mean of Rev1, Rev2, Rev3, and Rev4. Option A is incorrect because the range syntax with dash only works with numbered variables. Option C is incorrect because mean() requires the OF keyword when listing variables.

Multiple choice technology databases

Which one is single-row function

  1. STDDEV

  2. VARIANCE

  3. ROUND

  4. COUNT
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

ROUND operates on individual values, transforming each input row independently. In contrast, STDDEV, VARIANCE, and COUNT are aggregate functions that require processing multiple rows to compute statistical measures.

Multiple choice technology databases

How can we calculate average of a column?

  1. using AVG () function

  2. Using AVERAGE() function

  3. using SUM() and Count() functions

  4. using Total() function
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

To calculate the average of a column, you can either use the built-in AVG() aggregate function directly or divide the sum of the values using SUM() by the count of the values using COUNT(). Both methods produce the correct average.

Multiple choice technology

The below function helps in obtaining the running total

  1. cum

  2. cume

  3. cumulative

  4. cumu
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Informatica PowerCenter, the CUME() function calculates cumulative/running totals within a group. Unlike simple aggregation functions like SUM(), CUME maintains a running accumulation across rows, making it the correct choice for running total calculations.

Multiple choice technology programming languages

Which is not a group function?

  1. Count

  2. Avg

  3. Total

  4. Max
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Count, Avg, and Max are all standard SQL aggregate functions that operate on sets of rows in GROUP BY queries. Total is not a standard SQL aggregate function (SUM would be the correct function), making it the correct answer to 'which is NOT a group function.'

Multiple choice technology programming languages

You can use Avg or Sum group functions for any numeric data?

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Group functions like AVG and SUM can only be used on numeric columns that contain actual numeric data. They cannot be used on non-numeric data types (strings, dates, etc.) even if they appear numeric - the underlying data type matters. Additionally, these functions ignore NULL values in the numeric columns.

Multiple choice technology databases

Which column is more skewed? Total no. of rows in the table are 1000

  1. Deptno column has 5 distinct values, each having 200 rows

  2. Grade column has 2 distinct values having 1 and 999 rows

  3. Location column has 3 distinct values having 300, 400 and 300 rows

  4. All columns have same skewness
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Skewness measures data distribution unevenness. Grade column with 1 and 999 rows is extremely skewed - 99.9% of rows have one value. Deptno (200 each) and Location (300,400,300) have much more even distributions. Higher skewness means more uneven distribution, which affects query optimization and statistics collection.

Multiple choice technology databases

Which of the following is not a grouping function?

  1. avg

  2. count

  3. abs

  4. min
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Grouping (aggregate) functions operate on sets of values and return a single result. AVG, COUNT, and MIN are all standard SQL aggregate functions used with GROUP BY. ABS is a single-row numeric function that returns the absolute value of one number - it does NOT group or aggregate data, making it the correct answer.

Multiple choice technology

which of the following is the Volatile function?

  1. now

  2. sum

  3. then

  4. average
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

NOW() is a volatile Excel function because its value changes whenever the worksheet recalculates, even if no inputs change. Volatile functions automatically recalculate every time any cell is modified. SUM, THEN (not a real function), and AVERAGE are non-volatile.