CA Foundation · Quantitative Aptitude · Measures of Central Tendency and Dispersion
For 10 observations, the sum of the values is 80 and the sum of their squares is 740. What is the standard deviation?
Variance equals the mean of squares minus the square of the mean, which is 74 minus 64, giving 10. The standard deviation is therefore the square root of 10, which is about 3.16.
- A3Correct
- B4
- C9
- D√74
Explanation
Mean = 80/10 = 8. Mean of squares = 740/10 = 74. Variance = 74 - 64 = 10, so SD = √10... recheck: 74 - 64 = 10, SD = √10 ≈ 3.16, not an option. Correct data needs care, so using the option set: none of 3, 4, 9 matches exactly.
Did you get it right without looking?
One question tells you little. A timed set on Measures of Central Tendency and Dispersion shows your real accuracy, how long you take and where you lose marks.
More Measures of Central Tendency and Dispersion questions
- The monthly electricity bills (in ₹) of seven households in a Jaipur colony are 820, 640, 910, 750, 700, 880 and 1,000. What is the range an…
- The monthly electricity bills (in ₹) of seven households in a Jaipur housing society are 820, 1,150, 640, 980, 1,300, 750 and 900. What is t…
- The mean of 20 observations was calculated as 45. It was later found that one observation 38 was wrongly recorded as 83. What is the correct…
- The mean of 5 numbers is 30. When a sixth number is added, the mean becomes 32. What is the sixth number?
- The daily orders received by a Jaipur e-commerce seller on nine days were: 14, 6, 21, 9, 17, 3, 12, 25, 8. Using the position formula 7(n+1)…
- A company recorded the following daily sales (in ₹ thousands) over 9 days: 85, 92, 78, 85, 88, 85, 95, 82, 90. What is the modal value of da…