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Using a weighted mean is useful in situations where different population groups are contributing to an overall average, and you want to assign more influence to one group or the other based on a certain criteria. An arithmetic mean is a special case of the weighted mean where all the weights are equal. For example, let's say Population A of 2000 people has an average IQ of 140 and Population B of 100 people has an IQ of 90. You've been asked to determine the average IQ of the combined populations. Of course the correct thing to do would be to re-average all the combined individual scores, but let's say due to privacy reasons you don't have access to this information. The arithmetic mean of the two populations is (140+90)/2=115. However, Population A is much larger and contributes significantly more to the overall average, so you decide to weight based on population size. The weighted mean is (140*2000+90*100)/(2000+100) = 138, much closer to Population A's IQ. This is a fairer estimate of the overall average considering the relative population sizes. Weights are largely arbitrary, they don't always have to be based on population size alone. Let's say you have 5 reviewers of a product giving their overall satisfaction rating. The scores are 9, 7, 6, 7, 3. However you have a very high regard for Reviewer 1 so you assign her a weight of 15 (and the others remain at weight=1). The average score is 9+7+6+7+3/5=6.4 The weighted average score is 15*9+7+6+7+3/(15+4)=8.3 The weighted average is much closer to Review 1's opinion due to your weighting decision.
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What is the weighted average atomic mass of bromine?
The weighted average atomic mass of bromine is approximately 79.904 u. This value is calculated based on the natural abundance of bromine's isotopes.
Why do elements which exists as isotopes have fractional atomic mass?
Each isotope of an element has a different Atomic Mass, so an average is taken of all the isotopes, but the average is weighted because the natural abundance (%) of each isotope is factored in. If hydrogen-1 is much more abundant than deuterium and tritium, then the weighted average will be closer to 1 than 2 or 3 but not a whole number. The following equation shows how percent abundance factors into the weighted average. (atomic mass A)(X% abundance) + (atomic mass B)(Y% abundance)...=(weighted average of all isotopes of the element)(100% abundance)
Which of the following steps in the selection process is usually the most heavily Weighted?
screening interviews
What does the term adaptation mean?
To adjust oneself to different conditions, to suit a new or different purpose
Which best describes the definition of the atomic mass of an element?
it is the weighted average of the masses of an element's isotopes.
Is an arithmetic mean a weighted mean or a weighted mean an arithmetic mean?
The arithmetic mean is a weighted mean where each observation is given the same weight.
How do you get weighted mean?
A weighted mean is when some values contribute more than others. In order to calculate weighted mean multiply each weight by its value, add those and then divide by the sum of the weights.
The weighted mean is a special case for?
The weighted mean is simply the arithmetic mean; however, certain value that occur several times are taken into account. See an example http://financial-dictionary.thefreedictionary.com/weighted+average
Weighted mean sample problem?
weighted mean is getting the weighted average of students. normally, it is always use in computing the general average of the students to determine the ranking of the whole class.
The weighted mean is a special case of the?
Geometric mean
Is it the arithmetic mean or weighted mean that is more accurate Why?
The arithmetic mean and the weighted mean are used in different situations. The arithmetic mean is used in frequencies as a general average. The weighted mean is used when different factors contribute to some kind of total for example with weighted index numbers. It is not a matter of accuracy it involves using the right mean in the right situation. Almost always (if not always) a question will specify which mean to use.
What is the definition of 'weighted mean'?
"Weighted mean" is the average calculated by taking into account not only the frequencies of the variables but also some other factors such as their variance.
What is the purpose of having a weighted keyboard?
The purpose of a weighted keyboard is to better simulate playing an actual piano. Skilled piano players can achieve variations in the sounds produced by striking the weighted keys of a piano with different intensity. Additionally, since playing a piano or keyboard involves the use of muscles in the hands and arms, a weighted keyboard helps condition these muscles to better provide the strength and endurance to play an actual piano.
What is the formula for a weighted standard deviation?
Arithmatic Mean
What does wanos mean?
weighted average number of shares
What does rwa mean in finance?
Risk Weighted Assets
Is there any difference between expected value and arithmetic mean?
There is. Arithmetic mean is simple average of numbers not weighted by anything. However in EV, the numbers are weighted by their probability
