it saids to find the 7th number in the set of data
2006-10-05 09:19:27 · 3 answers · asked by Katherine V 1 in Education & Reference ➔ Homework Help
The mean is just the average, in this case 18. This means the sum of all 7 numbers is 126 (18 * 7).
126 minus all the other numbers will give you the answer.
2006-10-05 09:22:55 · answer #1 · answered by Sheik Yerbouti 4 · 0⤊ 0⤋
Okay - to find the mean you add all the numbers together and then divide by the number of numbers that there are in the set. So if you know what the mean is, then you can do it in reverse to find the missing number.
So multiply the mean by number of number in the set - so that'll be 18x7=126. Then subtract all the other numbers from that so 126-109= 17. Your missing number is 17. To check that we got it right, add all the numbers together and divide by the number of numbers. 17+15+13+8+17+20+36=126 126÷7=18. Tada!
2006-10-05 16:30:18 · answer #2 · answered by Seraphim 6 · 0⤊ 0⤋
(15+13+8+17+20+36+X) / 7 = 18
(109 + X) / 7 = 18
109 + X = 126 (multiply both sides by 7)
X = 17
You can put 17 back into the equation to check it!
2006-10-05 16:34:48 · answer #3 · answered by Go16 4 · 0⤊ 0⤋