Bissoy.com
Doctors Medicines MCQs Q&A

The mean of 20 observations is 17. On checking, it was found that the two observations were wrongly copied as 3 and 6. If the wrong observations are replaced with correct values 8 and 9, then what is the correct mean? 

The mean of 20 observations is 17. On checking, it was found that the two observations were wrongly copied as 3 and 6. If the wrong observations are replaced with correct values 8 and 9, then what is the correct mean?  Correct Answer 17.4

Mean of 20 observations is 17;

∴ Sum of 20 observations = 20 × 17 = 340

∵ 3 & 6 are replaced with 8 & 9;

Increase in the sum = 8 + 9 - 3 - 6 = 8

∴ Increased sum of 20 observations = 340 + 8 = 348

∴ Correct mean = 348/20 = 17.4

Related Questions

The mean of 10 observations is 27. Later, it was found that two observations were wrongly copied as 13 and 14. If wrong observations are replaced with 18 and 19, then what is the new mean? 
In a class of five students P, Q, R, S and T, only one student is known to have copied in the exam. The disciplinary committee has investigated the situation and recorded the statements from the students as given below. Statement of P: R has copied in the exam. Statement of Q: S has copied in the exam. Statement of R: P did not copy in the exam. Statement of S: Only one of us is telling the truth. Statement of T: R is telling the truth. The investigating team had authentic information that S never lies. Based on the information given above, the person who has copied in the exam is
Which of the following problems are decidable? I. Checking whether two regular languages are equivalent languages II. Checking whether two non-deterministic finite automata accept the same language III. Checking whether two context free grammars generate equivalent languages  IV. Checking whether a language of a context free grammar is non-empty
The mean of 5 observations is 60, the mean of 10 observations is 30 and the mean of 15 observations is 20. The mean of all the 30 observations is-
The median for an odd number of observations is _________ where n is the number of observations. rank on the ascending order of observations b) rank on the ascending order of observations c) Average of and (n/2) rank on the ascending order of observations d) (n/2) rank on the ascending order of observations
If the mean of m observations out of n observations is n and the mean of remaining observations is m, then what is the mean of all n observations?
How does number of observations influence overfitting? Choose the correct answer(s).Note: Rest all parameters are same
1. In case of fewer observations, it is easy to overfit the data.
2. In case of fewer observations, it is hard to overfit the data.
3. In case of more observations, it is easy to overfit the data.
4. In case of more observations, it is hard to overfit the data.
The mean of 10 observations is 13. Two more observations are included and the new mean becomes 14. The mean of two new observations is
Let p be the mean of m observations and q be the mean of n observations, where p ≤ q. If the combined mean of (m + n) observations is c, then which one of the following is correct?
Match the items of List - II with the items of List - I and select the code of correct matching List - I List - II (a) Chi-square Test (i) Testing the significance of the differences of the mean values among more than two sample groups. (b) ANOVA (F-test) (ii) Testing the goodness of fit of a distribution (c) Z - test (iii) Testing the significance of the difference of the mean values between two large sized samples (d) t - test (iv) Testing the significance of the difference of the mean values between two small sized samples when population standard deviation is not available