The mean of 5 observations is 15. If the mean of first three observations is 14 and that of the last three is 17, find the third observation.
Solution:
The mean of 5 observations = 15
So, total sum of the 5 observations = 15×5 = 75
Also given,
Mean of first 3 observations = 14
So, the sum of the 3 observations = 14×3 = 42
And, the mean of last 3 observations = 17
So, the sum of last 3 observations = 17×3 = 51
Thus, the total of 3 + 3 observations = 42 + 51 = 93
Hence, The third observation = 93 – 75 = 18.
The mean of 8 variate is 10-5. If seven of them are 3, 15, 7, 19, 2, 17 and 8, then find the 8th variate.
Solution:
Seven out of eight variates are: 3, 15, 7, 19, 2, 17 and 8
Mean of 8 variates = 10.5
So, the total of 8 variates = 10.5×8 = 84
Sum of seven variates = (3 + 15 + 7 + 19 + 2 + 17 + 8) = 71
Therefore, the 8th variate = 84 – 71 = 13.
More Solutions:
- If the median the data is 13, find the value of x
- State which of the following variables are continuous.
- Given below are the marks obtained by 27 students in a test:
- Explain the meaning of the following terms :
- The number of observations in a particular class.
- The marks obtained (out of 50) by 40 students in a test.
- Use the adjoining table to find:
- The marks of 200 students in a test were recorded.
- Given below are the marks secured by 35 students in a test: