Answer:
≈ 397 m
Step-by-step explanation:
Using Pythagoras' identity on the right triangle
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides.
Let h represent the height of the balloon above ground, then
h² + 50² = 400², that is
h² + 2500 = 160000 ( subtract 2500 from both sides )
h² = 157500 ( take the square root of both sides )
h ≈ 397 m ( to the nearest metre )
It travels 2144 in 8 hours.
Therefore, if you want to find out how many miles it travels in one hour, divide 2144 by 8.
2144 ÷ 8 = 268 miles in one hour. :)
It'd be too hard to comment the answer but here, lemme know if you aren't able to se it
Answer:
a) 

b) 

c) For this case when we increase the sample size the margin of error would be lower and then the interval would be narrower
d)
(a)
Solving for n we got:
(b)
And replacing the info we have:

Step-by-step explanation:
Part a
For this case we have the following data given
represent the sample mean for the customer order totals
represent the population deviation
represent the sample size selected
The confidence level is 90% or 0.90 and the significance level would be
and
and the critical value from the normal standard distirbution would be given by:

And the confidence interval is given by:

And replacing we got:


Part b
The sample size is now n = 75, but the same confidence so the new interval would be:


Part c
For this case when we increase the sample size the margin of error would be lower and then the interval would be narrower
Part d
The margin of error is given by:
(a)
Solving for n we got:
(b)
And replacing the info we have:
