Three sets of data on comparable situations are available as under:
Considering all the data sets together, the overall mean value would be:
If there are multiple datasets, containing some observations, their weighted mean can be calculated as – 
Where, x1, x2, …, and x3 are the mean of their respective datasets. n1, n2, …, and n3 are the total number of observations in each data set. So, in the given question, • x1 = 8, x2 = 7, and x3 = 9 • n1 = 9, n2 = 12, and n3 = 15 • Thereby overall mean = (8*9 + 12*7 + 15*9)/ (9+12+15) • = (72+84+135)/(36) • =291/36 = 8.08 • Hence option C is correct.
A cylindrical metal wire is reformed so that its length decreases by 20% with no change of volume. Its
resistance decreases by:
How many moles of carbon dioxide are present in a gas jar containing 1.501 × 1022 molecules of CO₂?
What is the ph of lemon juice?
Which of the following statements for the given chemical reaction is true?
Fe₂ O₃ + 2Al → Al₂ O₃ + 2Fe
An element "X", having atomic number 16. gains two electrons to form an anion X. What will be the atomic
number of 'X' in the anion?
In the given figure, frogs occupy ________.
An object is placed on the axis of a concave mirror at its focus (F). The image formed is:
Which among the following are present in higher amount in hard water?
The modern system of classification of living beings is based on the principles of
