The mean of 21 scores is found to be 73. Later, I discovered that this mean 73 is incorrect because one score was incorrectly reported as 66 in stead of 84. Now you state the correct mean. Report answer rounded to two decimal places.
2007-01-05 11:16:58 · 8 answers · asked by kwilliam21239 1 in Science & Mathematics ➔ Mathematics
By raising one score from 66 to 84, you increase the total by 18. The average therefore increases by 18/21 or 6/7.
The new mean will be 73 6/7 or 73.857142...
Rounded to two decimal places: 73.86
2007-01-05 11:20:22 · answer #1 · answered by Puzzling 7 · 1⤊ 0⤋
mean of 73 for 21 scores means that the sum of the 21 scores is 21*73=1533
correcting the score from 66 to 84 raises the sum by 84/66=18 so the sum is 1533+18=1551.
1551/21=73.86
2007-01-06 00:39:57 · answer #2 · answered by yupchagee 7 · 0⤊ 0⤋
The revised mean is:
73 +(84 - 66)/21 = 73 +18/21 = 73 6/7 = 73.86 to two decimals
2007-01-05 20:49:58 · answer #3 · answered by Northstar 7 · 0⤊ 0⤋
the mean of 21 scores is 73 so 73-66 =7 plus the correct one 7+84=91 and then the fraction 91/21=4.3333...
i think it's that ...
2007-01-05 19:32:35 · answer #4 · answered by leao 1 · 0⤊ 0⤋
work backwards to get the original total.
21 * 73 = 1533
take the erroneous score off...
1533 - 66 = 1467
Add the correct score on...
1467 + 84 = 1551
Now, calculate the correct average by dividing 1551 by 21
1551 divided by 21 = 73.857142857142857142857142857143
This score rounds to 74% (to the nearest whole percent).
2007-01-05 19:39:39 · answer #5 · answered by coachandybrown 2 · 0⤊ 0⤋
73.86
73* 21 = 1533
1533 - 66 + 84 = 1551
1551 / 21 = 73.8571
2007-01-05 19:22:05 · answer #6 · answered by Andrew T 1 · 1⤊ 0⤋
73.86
2007-01-05 19:35:04 · answer #7 · answered by Smarcher7623 2 · 0⤊ 0⤋
27.43
2007-01-05 19:19:23 · answer #8 · answered by Arnold 3 · 0⤊ 0⤋