Q73.The mean of a set of 30 observation is 75 . If each observations is multiplied by non-zero number λ and then each of them is decreased by 25 , their mean remains the same. Then, λ is equal to : (1) 4 (2) 1 3 3 (3) 10 (4) 2 3 3
What This Question Tests
This question is a direct application of the property of the mean under linear transformations. Students need to set up an equation where the transformed mean equals the original mean to solve for λ.
Concepts Tested
Formulas Used
If mean of x_i is X̄, then mean of ax_i + b is aX̄ + b
📚 NCERT Sections This Tests
12.5 — A Hydrogen Atom Initially In The Ground Level Absorbs A Photon,
Physics Class 12 · Chapter 12
12.5 A hydrogen atom initially in the ground level absorbs a photon, which excites it to the n = 4 level. Determine the wavelength and frequency of photon.
1.3 — Define The Following Terms:
Chemistry Class 11 · Chapter 1
1.3 Define the following terms: (i) Mole fraction (ii) Molality (iii) Molarity (iv) Mass percentage.
11.6 — The Threshold Frequency For A Certain Metal Is 3.3 × 1014 Hz. If Light
Physics Class 12 · Chapter 11
11.6 The threshold frequency for a certain metal is 3.3 × 1014 Hz. If light of frequency 8.2 × 1014 Hz is incident on the metal, predict the cut- off voltage for the photoelectric emission.
📋 Question Details
- Chapter
- Statistics
- Topic
- Mean of grouped/ungrouped data
- Year
- 2018
- Shift
- 15 Apr
- Q Number
- Q73
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 15: Statistics
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