Mean, Median & Mode (Railway Maths) (Part – I)

Total Questions: 50

11. What is the difference in the mode and the mean of the observation? 4, 5, 6, 7, 8, 12, 9, 12, 5, 12 [NTPC CBT II Level 6 (09/05/2022) Shift 1]

Correct Answer: (a) 4
Solution:

12. What will be the mean of all the prime numbers between 10 and 22? [NTPC CBT II Level 4 (10/05/2022) Shift 1]

Correct Answer: (b) 15
Solution:

13. If an observation 70 is removed from the data 60, 68, 70, 72, 74, 76, 78, 80 then the median is increased by: [NTPC CBT II Level 2 (13/06/2022) Shift 2]

Correct Answer: (b) 1
Solution:

14. The maximum weight lifted by 750 participants are recorded and it is found that the mean and the median of this distribution are both more than the mode. If the mean and the median are 184 kg and 178 kg respectively, then which of the following is the most likely value of the mode (in kg)? [NTPC CBT II Level 2 (13/06/2022) Shift 2]

Correct Answer: (d) 166
Solution:

Mean = 184 , Median = 178
We know, 3 × median = 2 × mean + mode
3 × 178 = 2 × 184 + Mode
Mode = 534 - 368 = 166

15. If mean is 40 and standard deviation is 5 then C.V (Coefficient of variation) is. [NTPC CBT-I 30/12/2020 (Morning)]

Correct Answer: (d) 12.5%
Solution:

16. Find the variance of the following data points: 6, 7, 5, 9, 12, 15 [NTPC CBT-I 03/02/2021 (Evening)]

Correct Answer: (d) 37/3
Solution:

17. Which of the following CANNOT take negative value? [NTPC CBT-I 10/02/2021 (Morning)]

Correct Answer: (a) Standard Deviation
Solution:

Standard Deviation can not take a negative value.

18. The variance of 20 observations is 5. If each observation is multiplied by 2, then the variance of the resulting observation will be: [NTPC CBT-I 10/02/2021 (Evening)]

Correct Answer: (c) 2² × 5
Solution:

19. If the variance of 5 values is 0.64, then what will be its standard deviation? [NTPC CBT-I 31/07/2021 (Evening)]

Correct Answer: (d) 0.8
Solution:

20. Find the mean of the first 10 consecutive odd numbers. [RRB JE 02/06/2019 (Afternoon) ]

Correct Answer: (c) 10
Solution:

Mean of the first ‘N’ consecutive odd numbers is always N. Therefore, the mean of the first 10 consecutive odd numbers is 10.