For the four test scores 96, 85, 91, and 86, the first 3 test ...

Question

For the four test scores 96, 85, 91, and 86, the first 3 test scores are 20% of the final grade, and the last test score is 40% of the final grade. Find the weighted mean of the test scores.

Accepted Answer

Hi, everyone, let's take a look at this practice problem. This problem says a student receives the following scores on four statistics projects 88, 94, 82, and 90. The projects contribute to the final grade with weights of 10%, 30%, 20%, and 40% respectively. What is the weighted average of the students' project scores? And we're given 4 possible choices as our answers. For choice A, we have 89.4%. For choice B, we have 90.2%. For Choice C, we have 86.0, and for choice D, we have 88.4. So here we just need to calculate the weighted average of the students' project scores. We recall to calculate the weighted average, you'll just take your scores and multiply them by their weights, and then add them up. So doing so, for our first project, we will have 88. As a score, and that gets multiplied by 10%, which we'll need that as a decibel, so divided by 100%, we'll get 0.1%. Then we'll have plus for a second project score, we had 94%, and that gets multiplied by 30%, which is going to be 0.3 as a decibel, then we'll have less. Our third score is 82. And that has a weight of 20%, so we'll multiply that by 0.2. And then we'll have plus for our final project score, we had 90. And that gets multiplied by a weight of 40%, so we'll multiply that by 0.4%. And so when we evaluate this expression, we get 89.4. So this here is the weighted average that we were looking for for this problem, and when we compare that to our answer choices, we see that the correct answer choice corresponds to answer choice A. So, I hope that this explanation has been useful, and I'll see you in the next video.

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