Answer:
1) The mean calculated for this case is
2)
3)
4) B. An interval estimate gives us a sense of the accuracy of the point estimate whereas a point estimate alone does not.
Because with the confidence interval we know the confidence level of the interval, and the limits for the parameter at some significance level.
Step-by-step explanation:
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".
Part 1
In order to calculate the mean and the sample deviation we can use the following formulas:
(a)
(b)
The mean calculated for this case is
The sample deviation calculated
population mean (variable of interest)
n=6 represent the sample size
Part 2
The confidence interval for the mean is given by the following formula:
(1)
So if we have the margin of error 5.4mm we can find the lowr limit like this:
Part 3
Part 4
B. An interval estimate gives us a sense of the accuracy of the point estimate whereas a point estimate alone does not.
Because with the confidence interval we know the confidence level of the interval, and the limits for the parameter at some significance level.
Answer:
The length of the longer ladder is 35 ft
Step-by-step explanation:
Please check the attachment for a diagrammatic representation of the problem
We want to calculate the length of the longer ladder ;
We make reference to the diagram
Since the two right triangles formed are similar. the ratios of their sides are equal;
Thus;
20/15 = 28/x + 15
20(x + 15) = 15(28)
20x + 300 = 420
20x = 420-300
20x = 120
x = 120/20
x = 6
So we want to calculate the hypotenuse of a right triangle with other sides 28ft and 21 ft
To do this, we use the Pythagoras’ theorem which states that square of the hypotenuse equals the sum of the squares of the two other sides
Let the hypotenuse be marked x
x^2 = 28^2 + 21^2
x^2 = 1,225
x = √1225
x = 35 ft
