The height of the given trapezoid is 7.5 m.
Step-by-step explanation:
Step 1:
The trapezoid's area is calculated by averaging the base lengths and multiplying it with the trapezoid's height.
The trapezoid's area,
Here is the lower base length and
is the upper base length while h is the height.
Step 2:
In the given problem, and
. Assume the height is h m.
The trapezoid's area
So the height of the given trapezoid is 7.5 m.
Answer:
a)
The standard error is given by:
And the margin of error is given by:
b) The 99% confidence interval would be given by (0.429;0.491)
Step-by-step explanation:
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".
The population proportion have the following distribution
Data given and notation
n=1024 represent the random sample taken
X=471 represent the people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering
estimated proportion of people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering
p= population proportion of people responded that they had used their cell phone while in a store within the last 30 days to call a friend or family member for advice about a purchase they were considering
Part a
The confidence interval would be given by this formula
For the 95% confidence interval the value of and
, with that value we can find the quantile required for the interval in the normal standard distribution.
The standard error is given by:
And the margin of error is given by:
Part b
If we replace the values obtained we got:
The 99% confidence interval would be given by (0.429;0.491)