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
4926.25965251
I used a calculator because it makes solving this much easier
Answer:
7 km
Step-by-step explanation:
Substitute:
The equation for area of a semi-circle is 
A =
76.97 =
Multiply by 2 on both sides:
2(76.97) = ( )2
153.94 = 
Divide by pi on both sides:
153.94 =
/pi /pi
49.03 ≈ 
Find the square root:
7 = r
Angle UQR = Angle UQX since they are corresponding angles. Note how the top polygon reflects over the line QU to get the bottom polygon.
So because of this, and because angle UQX = 45, this means the answer is 45 degrees
Add 13 to both sides, which leaves you with k=42.
