276÷ -0.12= I need the work shown, please.
1 answer:
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Answer:
(c, d) = (25, 35)
Step-by-step explanation:
Multiply the first equation by 2.5 and subtract the second one:
2.5(c +d) -(2.5c +1.75d) = 2.5(60) -(123.75)
0.75d = 26.25 . . . . . . . . . simplify
26.25/0.75 = d = 35 . . . . divide by the coefficient of d
60 -d = c = 25 . . . . . . . . . use the first equation to find c
(c, d) = (25, 35)
Answer:
A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07
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 of the interval is given by:
In this problem, we have that:
99.5% confidence level
So , z is the value of Z that has a pvalue of
, so
.
Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.07?
This is n when M = 0.07. So
A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07