Sq root of 64 =8 so sq root of 65 must be just a little larger than 8
<span>Therefore answer is between 8 & 9
</span>
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:
I need to know how many students there are to answer this question
The fourth proportionals are bc/a and st/r
<h3>How to determine the fourth proportional?</h3>
<u>Segments a, b and c</u>
Let the fourth segment be x.
So, we have the following equivalent ratio
a : b = c : x
Express as fraction
a/b = c/x
Make x the subject
x = bc/a
<u>Segments r, s and t</u>
Let the fourth segment be x.
So, we have the following equivalent ratio
r : s = t : x
Express as fraction
r/s = t/x
Make x the subject
x = st/r
Hence, the fourth proportionals are bc/a and st/r
Read more about proportions at:
brainly.com/question/1781657
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9.5, 9 4/5, 9.9
9 4/5 is equal to 9.8