The answer is 7 remainder 2.
Answer: W= -0.75
Explanation: 8 x -0.75= -6
-6 + 9= 3
1 and 17 are the only factors.
The confidence interval at 95% level is
7106.87 < μ< 14255.27
<h3>What is meant be mean and standard deviation?</h3>
The ratio of sum of observations to the total number of observation is known as mean. It is one of the central tendency in the statistics. It gives an idea about the central value present in the data. The most sensitive measure of central tendency is mean. It is very easy to calculate. Mean playa a crucial role in daily life. The two types of means are Arithmetic mean and Geometric mean.
Standard deviation is a measure in the statistics. The amount of variation of a set of values is known as standard deviation. Standard deviation is denoted by σ.
As per given data
90% confident level for amount of electricity used in community of Austin is
X-tx/2(n-1)s/√n < μ < X+ tx/2(n-1)s/√n
Here , n=12 , X=10681.07 , s=6893.87
Margin of error = tx/2(n-1)s/√n
=(1.796×6893.87)/√12
=3574.1996
=3574.19(approximately)
Therefore, 90% CI is,
10681.07-3574.19 ≤ μ<10681.07+3574.19
7106.87 < μ< 14255.27
To know more about mean and standard deviation, visit:
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Assume that the amount needed from the 5% solution is x and that the amount needed from the 65% solution is y.
We are given that, the final solution should be 42 ml, this means that:
x + y = 42 ...........> equation I
This can also be written as:
x = 42-y .......> equation II
We are also given that the final concentration should be 45%, this means that:
5% x + 65% y = 45% (x+y)
0.05x + 0.65y = 0.45(x+y)
We have x+y = 42 from equation I, therefore:
0.05x + 0.65y = 0.45(42)
0.05x + 0.65y = 18.9 .........> equation III
Substitute with equation II in equation III as follows:
0.05x + 0.65y = 18.9
0.05(42-y) + 0.65y = 18.9
2.1 - 0.05y + 0.65y = 18.9
0.6y = 18.9 - 2.1
0.6y = 16.8
y = 28 ml
Substitute with y in equation II to get x as follows:
x = 42-y
x = 42 - 28
x = 14 ml
Based on the above calculations:
amount of 5% solution = x = 14 ml
amount of 65% solution = y = 28 ml
The correct choice is:
The teacher will need 14 mL of the 5% solution and 28 mL of the 65% solution.