Answer:
c. 4.7
Step-by-step explanation:
first, you find the mean of data set:
83 + 85 + 82 + 93 + 83 + 84 + 95 + 87 + 86 + 94 = 872/10 = 87.2
then, you take each number and subtract the mean and square it:
(87.2 - 83)² = (4.2)² = 17.64
(87.2 - 85)² = (2.2)² = 4.84
(87.2 - 82)² = (5.2)² = 27.04
(93 - 87.2)² = (5.8)² = 33.64
(87.2 - 83)² = (4.2)² = 17.64
(87.2 - 84)² = (3.2)² = 10.24
(95 - 87.2)² = (7.8)² = 60.84
(87.2 - 87)² = (0.2)² = 0.04
(87.2 - 86)² = (1.2)² = 1.44
(94 - 87.2)² = (6.8)² = 46.24
now, find the mean of the squared numbers:
17.64 + 4.84 + 27.04 + 33.64 + 17.64 + 10.24 + 60.84 + 0.04 + 1.44 + 46.24 = 219.6/10 = 21.96
then, take the square root of the number you just got:
√21.96 = 4.68
and last but not least, round to the nearest tenth: 4.7
