# R makes calculating the weighted mean much easier

For most people, Google is necessary to understand what a weighted mean is and what it is used for if they are needing to incorporate some in their work. Thankfully, to calculate the weighted mean in R, a person just needs to decide how they plan to via the packages available. This can help a person display a simple average or a weighted average easier when they need to. This will take work to decide how to proceed from the start, but the work will make life easier in several areas. This is great tool for calculating the expected returns for a portfolio of business projects or investment opportunities.

### Useful Packages

There are a few packages that a person will need to consider if they are going to use a weighted mean in any of their calculations. The basic version of R has weighted.mean can handle the NA values with the right arguments. The dplyr package has the ability to let someone calculate the mean in a group situation. The matrixStats package has similar functionality as the basic build with the weightedMean command, along with the other commands. The SDMTools package allows for the wt.mean command to be used, which has more added benefits for programmers to utilize.

### Mathematical Definition

At the start, some who are not inclined toward mathematics may not fully understand the pages of information that is available. The basics to consider is that there are areas that are weighted for various reasons, and the numbers within these fields are multiplied accordingly. Taking a look at this from the perspective of grading, it can be easily explained. Say homework accounts for twenty percent of the grade, tests are at thirty percent, and the final test is at fifty percent and a person measures from there. This allows the weight to be measured in quantitative ways.

When looking for the weighted arithmetic mean, some people will not have all the data and will need to account for the missing values. There are arguments that can handle this when it is needed in required fields, which allows for the logical value to be handled in a common sense method. This could mean that people will need to create a matrix of sorts to handle how they see the numbers they will use. This may even require the use of vectors in how to plot out the numbers as they are calculated for the answers.

### Simple Coding

The simple coding for this can come in many forms, but the basic will look like this when making a program. The na.rm is to sort out the missing values when they are needed to be sorted.

weighted.mean(x, w, …, na.rm)

The SDMTool package will look quite similar, except for the primary command that is used.

wt.mean(x, w)

These commands will allow people to utilize various arguments and molding of them. A person may need to use a numerical vector and a weights vector for how they plan to use the numbers and make the data clear on a screen. It boils down to a complicated way to show how much money a company can make on paper becomes easily solved with knowing the right values for the program. This can help someone see what they could get from an investment or their own business. It will make the entire issue easier to see and to represent to others.

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