Answer:
He needs 92 on his last test.
Step-by-step explanation:
Mean score:
The mean is the sum of all scores divided by the number of tests.
In this question:
Scores of 85, 89, 85, 89 and x(the last one).
5 tests.
We want a mean of 88. So we find x for a mean of 88.
He needs 92 on his last test.
Not sure. Sorry.
Is this your homework??
The given data is
Scores: 90-99 80-89 70-79 60-69 50-59
Students: 3 7 12 4 4
Because we are to take the middle value for each group.
Therefore the total score is
Sx = 3*94.5 + 7*84.5 + 12*74.5 + 4*64.5 + 4*54.5 = 2245
The number of students is 3+7+12+4+4 = 30
The mean is
m =2245/30 = 74.833
Calculate (Sx - m)²
(Sx - m)² = 3*(94.5-74.833)² + 7*(84.5-74.833)² + 12*(64.5-74.833)²
+ 4*(64.5-74.833)² + 4*(54.5-74.833)² = 3896.7
Calculate the standard deviation
s = √(3896.7/29) = 11.592
Answer:
mean = 74.83
std. deviation = 11.59
Answer:
b
Step-by-step explanation:
The following radical phrase should be non-negative.
x - 3 ≥ 0
