Answer:
What is this for?
Step-by-step explanation:
Answer:
a) To determine the minimum sample size we need to use the formula shown in the picture 1.
E is the margin of error, which is the distance from the limits to the middle (the mean) of the confidence interval. This means that we have to divide the range of the interval by 2 to find this distance.
E = 0.5/2 = 0.25
Now we apply the formula
n = (1.645*0.80/0.25)^2 = 27.7 = 28
The minimum sample size would be 28.
b) To answer the question we are going to make a 90% confidence interval. The formula is:
(μ - E, μ + E)
μ is the mean which is 127. The formula for E is shown in the picture.
E = 0.80*1.645/√8 = 0.47
(126.5, 127.5)
This means that the true mean is going to be contained in this interval 90% of the time. This is why it doesn't seem possible that the population mean is exactly 128.
Answer:
(x, y) = (18, 5)
Step-by-step explanation:
Assuming the three lines meet at a single point at lower left (the figure is sloppily drawn), the angle (3x)°+49° is a corresponding angle to (7x-23)°. That means they have the same measure:
3x +49 = 7x -23
72 = 4x . . . . . . . . . add 23-3x
18 = x . . . . . . . . . . . divide by 4
__
Angles (3x)° and (11y-1)° are "corresponding" angles, so are congruent.
3x = 11y -1
3(18) +1 = 11y . . . . add 1, fill in the value of x
55/11 = y = 5 . . . . divide by 11
The values of x and y are 18 and 5, respectively.
Answer:
The answer is the last one:
4 , 10 , 18 , (k + 1)² + 3(k + 1) and k² + 5k + 4
Step-by-step explanation:
∵ 2 is a factor of n² + 3n
∵ n = 1 ⇒ ∴ (1)² + 3(1) = 1 + 3 = 4 ⇒ 2 is a factor of 4
∵ n = 2 ⇒ ∴ (2)² + 3(2) = 4 + 6 = 10 ⇒ 2 is a factor of 10
∵ n = 3 ⇒ ∴ (3)² + 3(3) = 9 + 9 = 18 ⇒ 2 is a factor of 18
∵ n = k + 1 ⇒ ∴ (k + 1)² + 3(k + 1) ⇒ before the simplify
∵ n = k + 1 ⇒ ∴ k² + 2k + 1 + 3k + 3 = k² + 5k + 4 ⇒ after simplify
Opposites.
Their sum is zero so they are called opposites.