If it is a fraction like (3a-3b)/(3a+12b)
= [3(a-b)]/[3(a+4b)]
= (a-b)/(a+4b)
The answer is: " 6.4 blocks " .
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3.2 blocks (one way), PLUS: 3.2 blocks the other way:
3.2 + 3.2 = 6.4 blocks .
or: (3.2) * 2 = 6.4 blocks .
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The answer is: " 6.4 blocks " .
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Answer:
The minimum sample size needed is 125.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
The margin of error is:
For this problem, we have that:
99% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
What minimum sample size would be necessary in order ensure a margin of error of 10 percentage points (or less) if they use the prior estimate that 25 percent of the pick-axes are in need of repair?
This minimum sample size is n.
n is found when 
So
Rounding up
The minimum sample size needed is 125.
Let's say we wanted to subtract these measurements.
We can do the calculation exactly:
45.367 - 43.43 = 1.937
But let's take the idea that measurements were rounded to that last decimal place.
So 45.367 might be as small as 45.3665 or as large as 45.3675.
Similarly 43.43 might be as small as 43.425 or as large as 43.435.
So our difference may be as large as
45.3675 - 43.425 = 1.9425
or as small as
45.3665 - 43.435 = 1.9315
If we express our answer as 1.937 that means we're saying the true measurement is between 1.9365 and 1.9375. Since we determined our true measurement was between 1.9313 and 1.9425, the measurement with more digits overestimates the accuracy.
The usual rule is to when we add or subtract to express the result to the accuracy our least accurate measurement, here two decimal places.
We get 1.94 so an imputed range between 1.935 and 1.945. Our actual range doesn't exactly line up with this, so we're only approximating the error, but the approximate inaccuracy is maintained.
