What is 5x-2y=4 6x+3y=-6
1 answer:
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Answer:
Sabemos que:
y tenemos que:
Con esto podemos encontrar el valor de a:
8*a/(a+ 4) = 6
8*a = 6*(a + 4) = 6*a + 24
8a - 6a = 24
2a = 24
a = 24/2 = 12.
Tambien sabemos que:
Y de ahí podemos despejar b:
(16*b)/(b + 8) = 12
16*b = 12*(b + 8) = 12b + 96
16b - 12b = 96
4b = 96
b = 96/4 = 24
Entonces tenemos a = 12 y b = 24, y el MH de a y b es:
MH(12,24) = 2*12*24/(12 + 24) = 24*24/36 = 16
Answer:
We need a sample size of at least 75.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, we find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The standard deviation is the square root of the variance. So:
With a .95 probability, the sample size that needs to be taken if the desired margin of error is 5 or less is
We need a sample size of at least n, in which n is found when M = 5. So
We need a sample size of at least 75.