Answer:
The first choice is the one you want
Step-by-step explanation:
Use geometric means to solve for a first. The formula is
and 64 = 15a and a = 64/15
That one was quite easy. Finding b is a bit more difficult.
The formula for finding b is
Solving for b:
Filling in we have
and
and
so b = 136/15
Answer:
The answer to your question is letter C
Step-by-step explanation:
This is a problem with the inverse rule of three because we expect that more machines can complete the same work in fewer days.
6 machines ------------------ 12 days
x machines ------------------- 8 days
x machines =
x = 4 machines
Answer:
n=126
Step-by-step explanation:
Data given and previous concepts
represent the sample mean
represent the sample deviation
n=32 represent the sample size
Confidence =0.95 or 95%
represent the significance level
ME= 2 represent the margin of error required
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
Assuming the X follows a normal distribution
Solution to the problem
Since we don't have the population deviation. We know that the margin of error for a confidence interval is given by:
(1)
The next step would be find the value of ,
and
. The degrees of freedom are given by:
Using the normal standard table, excel or a calculator we see that:
And the code in excel is this one: "=T.INV(1-0.025,31)"
If we solve for n from formula (1) we got:
And we have everything to replace into the formula:
And if we round up the answer we see that the value of n to ensure the margin of error required is n=126.