kali bought 6 books for a total of $154. math books cost $27 and English books cost $23. how many of each type of book did she b
1 answer:
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Answer:
Length: 139 feet
Width: 104 feet
Step-by-step explanation:
The formula for the perimeter of a rectangle can be given by . We are given the perimeter of the pool along with the width.
From here, all we have to do is plug back into the original formula:
Which can be further simplified as:
From here, all we have to do is add 70 to both sides of the equation and divide by four:
To make sure that this answer is accurate, we can find that the width of the rectangle should then be 104 (given by 139 - 35). All we have to do is plug back into the original equation:
And the substitution works, so the length of the rectangle would be 139 feet and the width would be 104 feet.
Answer:
a) The 99% confidence interval would be given by (346.708;453.292)
b) The 99% confidence interval would be given by (338.445;461.555)
Step-by-step explanation:
1) Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
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".
represent the sample mean for the sample
population mean (variable of interest)
represent the population standard deviation
n=15 represent the sample size
2) Part a
The confidence interval for the mean is given by the following formula:
(1)
Since the Confidence is 0.99 or 99%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 99% confidence interval would be given by (346.708;453.292)
3) Part b
For this case we don't know the population deviation so we need to use the t distribution instead the normal standard distribution.
The confidence interval for the mean is given by the following formula:
(1)
We need to find the degrees of freedom first df=n-1=15-1=14
Since the Confidence is 0.99 or 99%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,14)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 99% confidence interval would be given by (338.445;461.555)