A bird is flying northeast. In the same time it flies 3/5 mile east, it flies 5/6 mile north. How many miles does the bird fly e
1 answer:
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Answer:
Step-by-step explanation:
The above question is in the form of an exponential decay. The equation for an exponential decay is given by:
where y and x are variables, b < 1, a is the initial value of y (that is the value of y when x = 0).
Let y represent the number of trees left and x represent the number of months. Given that there is currently 2.5 billion trees, therefore a = 2.5 * 10⁹, b = 0.5% = 0.005. The equations becomes:
Answer:
And rounded up we have that n=656
Step-by-step explanation:
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 80% of confidence, our significance level would be given by and
. And the critical value would be given by:
Solution to the problem
The margin of error for the proportion interval is given by this formula:
(a)
Since we don't have prior info for the proportion of interest we can use as estimator. And on this case we have that
and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
And replacing into equation (b) the values from part a we got:
And rounded up we have that n=656