examples of mean

Question

how to find mean and mode when you have unknown value in the list

Answer 1

You could write the mean in terms of the unknown:

2, 2, 4, x

mean = (2 + 2 + 4 + x) / 4 <--- sum of all terms divided by the number of terms

= (8 + x)/ 4    or       2 + x/4

 

For the mode, you would need to consider that the unknown could be any number. Take the above example:

2, 2, 4, x

The mode could be 2, but if x were a 4 that would also be a mode. Depending on your teacher and textbook,you would say there are two modes (if x=4 modes: 2, 4, else mode = 2) or no mode. Ask your teacher before your next test to see what he/she goes by.

Answer 2

I'd need to see the exact question to be sure, but I think the explanation below should help.

Mode should be the same.  Whichever # is repeated most often.  If you have multiple repetitions of an unknown, it could end up being your mode.

Example A: 2, 4, 5, 3, 4, 6, x, 4, 2 => In this case, the mode is 4.

Example B: 2, 4, x, 3, x, 5, 4, x, 1 => In this case, the mode is x.

Remember that within a problem x is x and has the same value, you just don't know what it is.  The value of x will only change when you move to the next problem.

Now lets find the mean of both of those examples.  You'll simply have to answer with an equation.

Example A: 2+4+5+3+4+6+x+4+2 OR 2+4+5+3+4+6+4+2 = 30 and then add in your x, so 30+x

You have a total of 9 terms, so the answer would be (30+x)/9

Example B: 2+4+x+3+x+5+4+x+1 OR 2+4+3+5+4+1 = 19 and then add x+x+x, so 19+3x

You again have 9 terms, so the answer would be (19+3x)/9

If your teacher is picky about simplification, that would be (19/9) + (x/3)

Hope that helped!