The mean is the average of all the numbers in the data set.

Add the numbers.

\(\displaystyle 2+(-8)+9+36 = 39\)

Divide this number by four.

The answer is:  \(\displaystyle \frac{39}{4}\)

Let \(\displaystyle x\) be the unknown scores for Danielle's last two exams. Set up an equation such that the sum of all exam grades over six is equal to seventy, since this is the passing score.

\(\displaystyle \frac{50+65+60+55+x+x}{6} = 70\)

Multiply both sides by six.

\(\displaystyle \frac{50+65+60+55+x+x}{6} \cdot 6= 70\cdot 6\)

\(\displaystyle 50+65+60+55+x+x=420\)

Sum the numbers.

\(\displaystyle 230+2x = 420\)

Subtract 230 from both sides.

\(\displaystyle 2x=190\)

Divide by two on both sides.

\(\displaystyle \frac{2x}{2}=\frac{190}{2}\)

Simplify both sides.

\(\displaystyle x=95\)

Danielle must average at least a \(\displaystyle 95\) on both her last two exams in order to pass her class.

The mean is the average of all the numbers in the data set.

Add all the numbers.

\(\displaystyle -3+3+10+13+23=46\)

Since there are five numbers, divide this number by five.

The answer is:  \(\displaystyle \frac{46}{5}\)

The mean is the average of all the numbers given in the data set.

Add the numbers.

\(\displaystyle -9+(-1)+1000 = -10 +1000 = 990\)

Divide this number by three.

\(\displaystyle \frac{990}{3} = 330\)

The mean is:  \(\displaystyle 330\)

Write an expression to sum the numbers.  Enclose the negative numbers in parentheses.

\(\displaystyle (-19)+36+14+(-5) = 26\)

Divide this number by four.

\(\displaystyle \frac{26}{4}\)

Reduce this fraction.  Both the numerator and denominator are divisible by two.

\(\displaystyle \frac{26}{4}=\frac{13\times 2}{2\times 2}\)

Cancel out the twos.

The answer is:  \(\displaystyle \frac{13}{2}\)

The mean is the sum of all the numbers divided by the total amount of numbers in the data set.  It is also the average.

Add the numbers.

\(\displaystyle 0+0+0+1+1+1+2+3+4=12\)

There are nine numbers provided.

Divide the sum with nine.

\(\displaystyle \frac{12}{9} = \frac{4}{3}\)

The mean is:  \(\displaystyle \frac{4}{3}\)

The best way to solve this is to first determine what her final total score should be. If she needs an average of \(\displaystyle 85\), with a total of \(\displaystyle 4\) tests, she must achieve a total score of \(\displaystyle 340\) (which is \(\displaystyle 85\cdot4\)). Then, to determine what score she must achieve on the final test, we simply subtract her previous scores. \(\displaystyle 340-(76+91+83)=340-250=90\). So her final score must be at least \(\displaystyle 90\) if she is going to achieve her goal.

To find the average, we simply add all of the scores together and divide by the number of tests (in this case \(\displaystyle 5\)). We find a sum of \(\displaystyle 390\), and when we divide by 5, we find a final average score of \(\displaystyle 78\).

Add up all of the values in the data set and divide the sum by the number of values of the set.

\(\displaystyle 4+ 14+8+4+2+15+ 18+ 20+ 5+ 10 = 100\)

\(\displaystyle 100 \div 10 = 10\)

Find the mean of the following data set:

\(\displaystyle 16,77,83,16,23,99,55,77,23,16\)

Whenever we are working with a data set, it can be helpful to put the terms in order:

\(\displaystyle 16,16,16,23,23,55,77,77,83,99\)

Now that our terms are in order, we can do all sorts of things with them.

In this case, we need to find the mean. This is essentially the same as the average. 

Begin by finding the sum of our terms.

\(\displaystyle 16+16+16+23+23+55+77+77+83+99=485\)

Now, because we have ten terms, we need to divide by 10

\(\displaystyle \frac{485}{10}=48.5\)