Answer:
There is a 95% confidence that the sample has a mean between 158.92 pounds and 171.48 pounds
Step-by-step explanation:
Given that mean (μ) = 165.2 pounds, standard deviation (σ) = 12.4 pounds, sample size (n) = 15 crates. Confidence (C) = 95% = 0.95
α = 1 - C = 1 - 0.95 = 0.05
α/2 = 0.05/2 = 0.025
The z score of α/2 corresponds to the z score of 0.475 (0.5 - 0.025) which is 1.96. 
The margin of error (E) is given by:
The confidence interval = μ ± E = 165.2 ± 6.28 = (158.92, 171.48)
The confidence interval is between 158.92 pounds and 171.48 pounds. There is a 95% confidence that the sample has a mean between 158.92 pounds and 171.48 pounds
Answer:
580
Step-by-step explanation:
Let's translate this word for word.
87 is 15% of what number
87 = 15% times x
87=.15 times x
Divide both sides by .15
Cancel out the common factor of .15 on the right; that is .15/.15=1.
580 is the number
Answer:
Step-by-step explanation:
Firstly, note that -2i really is just z = 0 + (-2)i, so we see that Re(z) = 0 and Im(z) = -2.
When we're going from Cartesian to polar coordinates, we need to be aware of a few things! With Cartesian coordinates, we are dealing explicitly with x = blah and y = blah. With polar coordinates, we are looking at the same plane but with angle and magnitude in consideration.
Graphing z = -2i on the Argand diagram will look like a segment of the y axis. So we ask ourselves "What angle does this make with the positive x axis? One answer you could ask yourself is -90°! But at the same time, it's 270°! Why do you think this is the case?
What about the magnitude? How far is "-2i" stretched from the typical "i". And the answer is -2! Well... really it gets stretched by a factor of 2 but in the negative direction!
Putting all of this together gives us:
z = |mag|*(cos(angle) + isin(angle))
= 2*cos(270°) + isin(270°)).
To verify, let's consider what cos(270°) and sin(270°) are.
If you graph cos(x) and look at 270°, you get 0.
If you graph sin(x) and look at 270°, you get -1.
So 2*(cos(270°) + isin(270°)) = 2(0 + -1*i) = -2i as expected.
Answer:
(-2, -3)
(3, 12)
Step-by-step explanation:
To solve this, we're gonna get rid of the y's with substitution
x² + 2x - 3 = 3x + 3
Let's make this equation equal to zero
Subtract 3 from both sides
x² + 2x - 3 = 3x + 3
- 3 - 3
x² + 2x - 6 = 3x
Subtract 3x from both sides
x² + 2x - 6 = 3x
- 3x - 3x
x² - x - 6 = 0
Factor the equation
(x - 3)(x + 2) = 0
This means x can be -2 or 3
Let's solve it with -2 first, plug the new x in y = 3x + 3
y = 3(-2) + 3
y = -6 + 3 = -3
Do the same for x = 3
y = 3(3) + 3
y = 9 + 3 = 12
Answer:62
Step-by-step explanation: 62
