Answer:
Step-by-step explanation:
The formula for determining the confidence interval for the difference of two population means is expressed as
Confidence interval = (x1 - x2) ± z√(s²/n1 + s2²/n2)
Where
x1 = mean sale amount for mail order sales = 82.70
x2 = mean sale amount for internet sales = 66.9
s1 = sample standard deviation for mail order sales = 16.25
s2 = sample standard deviation for internet sales = 20.25
n1 = number of mail order sales = 17
n2 = number of internet sales = 10
For a 99% confidence interval, we would determine the z score from the t distribution table because the number of samples are small
Degree of freedom =
(n1 - 1) + (n2 - 1) = (17 - 1) + (10 - 1) = 25
z = 2.787
Margin of error =
z√(s²/n1 + s2²/n2) = 2.787√(16.25²/17 + 20.25²/10) = 20.956190
Answer:
X = 48
Step-by-step explanation:
When you type sin(42) in your calculator it will give you something around 0.669.
If you try reverse sinus sin-1(0.669) it will give you 42.
Therefore you can say that:
Cos(x) = 0.669
So you can reverse the cos to get your answer
Cos-1(0.669) = 48
Or
Cos-1 (sin(42))
Answer:
Step-by-step explanation:
You can identify similar polygons by comparing their corresponding angles and sides. As you see in the following figure, quadrilateral WXYZ is the same shape as quadrilateral ABCD, but it’s ten times larger (though not drawn to scale, of course). These quadrilaterals are therefore similar.
similar polygons: For two polygons to be similar, both of the following must be true:
Corresponding angles are congruent.
Corresponding sides are proportional.
To fully understand this definition, you have to know what corresponding angles and corresponding sides mean. (Maybe you’ve already figured this out by just looking at the figure.) Here’s the lowdown on corresponding. In the figure, if you expand ABCD to the same size as WXYZ and slide it to the right, it’d stack perfectly on top of WXYZ.
