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 20 are left
Step-by-step explanation:
For question 13, you need to look at all the numbers that are less than 1/2 and then count the number of marks in total .
Answer: 7 B
For question 14, you need to first make an equation that suits the circumstances and the situations in this problem.
$25+$24x=$193
$24x=$168
x=7 weeks
x stands for the number of weeks that she has to wait for in order to save enough money to purchase the camera.
Answer: 7 weeks A
Answer:
{x:x is a natural number less than 6}
Step-by-step explanation:
Set builder is a type of set where we have to represent any value inside a set
by using the variable x, v, b, a, c etc.
Eg A={1,2,3,4}
For eg {a: a is a natural number less than 5}
Answer:
Heavenly, we need the forumula for the area of a triangle, do you know it?
Step-by-step explanation:
Area of a triangle is (1/2 ) * B*H
where B = base
H = height
then
A = 1/2* B * H
A is given to be 20
B = b
H = b+4
plug all those into the formula,
20 = (1/2)*b*(b+4)
use your algebra skillz :P
20 = 1/2 *( 
+ 4b)
20*2 = + 4b
40 = + 4b
0 = + 4b-40
rewrite the above so it's in x format
+ 4x -40 = 0
use the quadratic formula to find x , and for our problem, remember that x represents the base, or b, but don't mix it up with the b in the quadatic fomula, with the b of the triangle, which is the base, they are differnt "b"s :P
X = (b±
) / 2*a
a = 1
b = 4
c = -40
x = (4±
) /2*1
x = ( 4±
) / 2
x = (4±
) / 2
x = (4±13.266499)/2
x= 2±6.633249
x = 2 + 6.633249 = 8.633
b= 8.633 cm
