Answer:
The point estimate that should be used in constructing the confidence interval is 3.5.
The 95% confidence interval for the true mean difference between the mean height of the American students and the mean height of the non-American students, in inches, is (2.25, 4.75).
Step-by-step explanation:
Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
American students:
Sample of 12, mean height of 68.4 inches with a standard deviation of 1.64 inches. This means that:
[tex]\mu_A = 68.4[/tex]
[tex]s_A = \frac{1.64}{\sqrt{12}} = 0.4743[/tex]
Non-American students:
Sample of 17, mean height of 64.9 inches with a standard deviation of 1.75 inches. This means that:
[tex]\mu_N = 64.9[/tex]
[tex]s_N = \frac{1.75}{\sqrt{17}} = 0.4244[/tex]
Distribution of the difference:
[tex]\mu = \mu_A - \mu_N = 68.4 - 64.9 = 3.5[/tex]
[tex]s = \sqrt{s_A^2+s_N^2} = \sqrt{0.4743^2 + 0.4244^2} = 0.6365[/tex]
The point estimate that should be used in constructing the confidence interval is 3.5.
Confidence interval:
[tex]\mu \pm zs[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
95% confidence level
So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].
The lower bound of the interval is:
[tex]\mu - zs = 3.5 - 1.96*0.6365 = 2.25[/tex]
The upper bound of the interval is:
[tex]\mu + zs = 3.5 + 1.96*0.6365 = 4.75[/tex]
The 95% confidence interval for the true mean difference between the mean height of the American students and the mean height of the non-American students, in inches, is (2.25, 4.75).
A survey is conducted to determine the percentage of students at state universities who change their major at least once. In a study of 100 students 78% indicated that they graduated with a major different from the one with which they entered college. Determine a 90% confidence interval for the percentage of students who change their major.
Answer:
Step-by-step explanation:
Confidence Level - "P" values
90% 1.645
Confidence Interval - "P" values
(0.7119 , 0.8481 )
How many times greater is
3.8 X 10^5 than
1.9 X 10^2
2
20
200
2000
Answer:
2 * 10^3 = 2000.
Step-by-step explanation:
3.8/1.9 * 10^5/10^2
= 2 * 10^3
which of the following are ordered pairs for the given function f(x)=1+x.? (1,2) (3,3) (0,2) (1,0) (0,1)
Answer:
no,
(
1
,
0
)
is not an ordered pair of the function
f
(
x
)
=
1
+
x
.
Step-by-step explanation:
Ordered pairs are usually written in the form
(
x
,
y
)
by tradition.
so usingthe function,
f
(
x
)
=
1
+
x
we can rewrite it as,
y
=
1
+
x
any pair of x and y that satisfy this equation are solutions to the equation.
so subbing in
(
1
,
0
)
,
0
=
1
+
(
1
)
0
=
2
which is not true so the point does not make the function true.
It might be easier to see graphically,
graph{1+x [-10, 10, -5, 5]}
any combination of x and y on this line make the equation true and as such are an ordered pair of the function.
Answer:
Step-by-step explanation:
sin4x.sin5x+sin4x.sin3x-sin2x.sinx=0
Recall the angle sum identity for cosine:
cos(x + y) = cos(x) cos(y) - sin(x) sin(y)
cos(x - y) = cos(x) cos(y) + sin(x) sin(y)
==> sin(x) sin(y) = 1/2 (cos(x - y) - cos(x + y))
Then rewrite the equation as
sin(4x) sin(5x) + sin(4x) sin(3x) - sin(2x) sin(x) = 0
1/2 (cos(-x) - cos(9x)) + 1/2 (cos(x) - cos(7x)) - 1/2 (cos(x) - cos(3x)) = 0
1/2 (cos(9x) - cos(x)) + 1/2 (cos(7x) - cos(3x)) = 0
sin(5x) sin(-4x) + sin(5x) sin(-2x) = 0
-sin(5x) (sin(4x) + sin(2x)) = 0
sin(5x) (sin(4x) + sin(2x)) = 0
Recall the double angle identity for sine:
sin(2x) = 2 sin(x) cos(x)
Rewrite the equation again as
sin(5x) (2 sin(2x) cos(2x) + sin(2x)) = 0
sin(5x) sin(2x) (2 cos(2x) + 1) = 0
sin(5x) = 0 or sin(2x) = 0 or 2 cos(2x) + 1 = 0
sin(5x) = 0 or sin(2x) = 0 or cos(2x) = -1/2
sin(5x) = 0 ==> 5x = arcsin(0) + 2nπ or 5x = arcsin(0) + π + 2nπ
… … … … … ==> 5x = 2nπ or 5x = (2n + 1)π
… … … … … ==> x = 2nπ/5 or x = (2n + 1)π/5
sin(2x) = 0 ==> 2x = arcsin(0) + 2nπ or 2x = arcsin(0) + π + 2nπ
… … … … … ==> 2x = 2nπ or 2x = (2n + 1)π
… … … … … ==> x = nπ or x = (2n + 1)π/2
cos(2x) = -1/2 ==> 2x = arccos(-1/2) + 2nπ or 2x = -arccos(-1/2) + 2nπ
… … … … … … ==> 2x = 2π/3 + 2nπ or 2x = -2π/3 + 2nπ
… … … … … … ==> x = π/3 + nπ or x = -π/3 + nπ
(where n is any integer)
look at the image below
Which is the same length as 4 kilometers?
Answer:
A. 4000 meters because
1 km = 1000 meters
and 4 km = 1000 × 4 = 4000
............
Cho hệ vectơ:
X1=(2;1;0;1); X2=(1;1;0;-1); X3=(0;-1;2;2); X4=(1;0;2;1)
a) Xét xem hệ vectơ trên độc lập tuyến tính hay phụ thuộc tuyến tính.
b) Biểu diễn vectơ X 4 qua các vectơ còn lại.
Answer:
i dont no the ans
Step-by-step explanation:
A scientist has two solutions, which she has labeled Solution A and Solution B. Each contains salt. She knows that Solution A is 55% salt and Solution B is 70% salt. She wants to obtain 30 ounces of a mixture that is 60% salt. How many ounces of each solution should she use?
Answer:
Let x = the number of ounces of Solution A
Let y = the number of ounces of Solution B
x + y = 180 y = 180 - x
.60x + .85y = .75(180)
.60x + .85y = 135 Multiply both sides of the equation by 100 to remove the decimal points.
60x + 85y = 13500
60x + 85(180 - x) = 13500
60x + 15300 - 85x = 13500
-25x = -1800
x = 72ounces
y = 180 - 72
y = 108 ounces
Step-by-step explanation:
Wyzant (ask an expert) solution on their website.
find out the area of the following composite figures
Help 50 point question
Answer:
1/3
Step-by-step explanation:
.444444444(repeating)- .111111111111(repeating)
.44444444......
-.11111111........
--------------------
.33333333........
Let x = .3333333.....
10x = 3.3333333.....
Subtract the first equation from the second
10x = 3.33333.....
-x = .33333.....
--------------------------
9x = 3
x = 3/9
x = 1/3
---------------------------
write down the length of the diameter of the circle
Answer:
Diameter = 2 × Radius
Step-by-step explanation:
Answer:
Step-by-step explanation:
The diameter of a circle is the length of the line through the center and touching two points on its edge. In the figure above, drag the orange dots around and see that the diameter never changes. The diameter is also a chord.
(x - 7)2 = x2 - 49
O True
O False
Answer:
False
Step-by-step explanation:
The length of a rectangle is (x+1) cm, and its width is 5 cm less than its length.
a) Express the area of the rectangle, A cm^2 , in terms of x.
b) The area of the rectangle is 24 cm^2. Calculate the length and width of the rectangle.
Answer:
a) x^2-3x-4(you also can express it as (x+1)(x-4))
b)The length is 8 cm, the width is 3 cm
Step-by-step explanation:
a) The length is x+1
The width is (x+1-5)= x-4
The area is the product of the length and the width
(x+1)(x-4)= x^2-3x-4
b) The formula for counting the area is x^2-3x-4
It is equal to 24
S0 x^2-3x-4=24
x^2-3x-28=0
a=1 b=-3 c=-28
D= b^2-4ac= 3^2-4*(-28)= 9+112= 121
sqrtD= 11
x1= (-b-sqrtD)/2a=(3-11)/2=-4 The length is -4+1=-3<0, but the length must be positive, this root isn't suitable.
x2= (-b+sqrtD)/2a=(3+11)/2=7 The length is 7+1=8 (it is suitable)
8-5=3 - The width
a grocery store cashier packed 2 carts of groceries equally into 12 paper bags. what fraction of a cart is in each bag?
Answer:
Step-by-step explanation:
(2 carts)/(12 bags) = (⅙ cart)/bag
Need the help thanks guys
Answer:
x=−5+√29 or x=−5−√29
Step
Let's solve your equation step-by-step.
x2+10x+10=14
Step 1: Subtract 14 from both sides.
x2+10x+10−14=14−14
x2+10x−4=0
For this equation: a=1, b=10, c=-4
1x2+10x+−4=0
Step 2: Use quadratic formula with a=1, b=10, c=-4.
x=
−b±√b2−4ac
2a
x=
−(10)±√(10)2−4(1)(−4)
2(1)
x=
−10±√116
2
x=−5+√29 or x=−5−√29
what is 5.5 feet in centimeters?
Answer:
167.64 cm
Step-by-step explanation:
I dont kno how to work it out
Geometry please help me!In the figure below, what value of x will satisfy the midsegment theorea? X=
Answer:
x=30.5
Step-by-step explanation:
Using midsegment 's theorea:
[tex]2=\dfrac{RG}{RS} =\dfrac{RH}{RQ} =\dfrac{GH}{SQ} \\\\4x-65=2x-4\\\\2x=61\\\\x=\dfrac{61}{2} \\\\x=30.5\\[/tex]
A population of deer in Florida grows according to a logistic model, with r = 0.17 and K = 10,000. At what population size is the per capita population growth rate the highest? Group of answer choices N = 1000 N = 5000 N = 8000 N = 10000
Answer:
N = 1000
Step-by-step explanation:
The population growth of species per capita of any geographical can be computed by using the formula:
[tex]\dfrac{dN}{dT}=rN (1 - \dfrac{N}{K})[/tex]
here;
N = population chance
T = time taken
K = carrying capacity
r = the constant exponential growth rate
From the given equation, we can posit that the value of r will be the greatest at the time the value of dN is highest:
As such, when the population chance = 1000
[tex]\dfrac{dN}{dT}=0.17 * 1000 (1 - \dfrac{1000}{10000})[/tex]
[tex]\dfrac{dN}{dT}=0.17 * 1000 (0.9)[/tex]
[tex]\dfrac{dN}{dT}= 153[/tex]
At N = 5000;
[tex]\dfrac{dN}{dT}= 85[/tex]
At N= 8000;
[tex]\dfrac{dN}{dT}= 34[/tex]
At N = 10000
[tex]\dfrac{dN}{dT}= 0[/tex]
PLS HELP I DONT KNOW THIS ONE
Answer:
x+3
---------------
(x-3)(x-2)(x-4)
Step-by-step explanation:
x+4 x^2 -16
---------------÷ -------------
x^2 - 5x+6 x+3
Copy dot flip
x+4 x+3
--------------- * -------------
x^2 - 5x+6 x^2 -16
Factor
x+4 x+3
--------------- * -------------
(x-3)(x-2) (x-4)(x+4)
Cancel like terms
1 x+3
--------------- * -------------
(x-3)(x-2) (x-4)1
x+3
--------------- x cannot equal 3,2,4 -4
(x-3)(x-2)(x-4)
is y=x^2 a proportional relationship?
is y=2+x a proportional relationship?
is y=2/x a proportional relationship?
is y=2x a proportional relationship?
Answer:
is y=x^2 a proportional relationship?
[tex]{ \sf{yes. \: constant \: of \: proportionality = 1}}[/tex]
is y=2+x a proportional relationship?
[tex]{ \sf{no. \: unless \: y \: is \: proportinal \: to \: (2 + x)}}[/tex]
is y=2/x a proportional relationship?
[tex]{ \sf{yes. \: where \: proportianality \: constant \: is \: 2}}[/tex]
is y=2x a proportional relationship?
[tex]{ \sf{yeah. \: constant \: is \: 2}}[/tex]
This answer was confusing for sure
Explanation:
Normally, y = cos(x) has a period of 2pi. This means that every 2pi horizontal units, the graph repeats itself. However, we can see that the period here is pi units instead.
One way to see this is to start at (0,1). This is a local max point. Move to its neighboring local max at (pi,1). We have moved pi units along the x axis and the cycle is finished, after which point the cycle repeats itself.
Since T = pi is the period, we then can say B = 2pi/T = 2pi/pi = 2
This is then plugged into y = A*cos(B(x-C))+D where
A = 1
C = 0
D = 0
That leads us to y = cos(2x)
Since the period is often connected to time values, it might help to think of this wave's oscillations occurring twice as often compared to y = cos(x). So that might help see why we replace the x with 2x.
The vertex form of the equation of a parabola is y =
standard form of the equation?
Y=1/2(x - 4)^2 +13. What is the
O A. y-2x2-8x+29
O B. y=zx2 - 4x +21
O C. y=1* -8x+21
O D. y - 4x2 - 4x +29
Answer:
Step-by-step explanation:
y = ½(x-4)² + 13
y = ½(x² - 8x + 16) + 13
y = ½x² - 4x + 21
a test for diabetes results in a positive test in 95% of the cases where the disease is present and a negative test in 07% of the cases where the disease is absent. if 10% of the population has diabetes, what is the probability that a randomly selected person has diabetes, given that his test is positive
Answer:
0.9378 = 93.78% probability that a randomly selected person has diabetes, given that his test is positive.
Step-by-step explanation:
Conditional Probability
We use the conditional probability formula to solve this question. It is
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]
In which
P(B|A) is the probability of event B happening, given that A happened.
[tex]P(A \cap B)[/tex] is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Positive test
Event B: Person has diabetes.
Probability of a positive test:
0.95 out of 0.1(person has diabetes).
0.007 out of 1 - 0.1 = 0.9(person does not has diabetes). So
[tex]P(A) = 0.95*0.1 + 0.007*0.9 = 0.1013[/tex]
Probability of a positive test and having diabetes:
0.95 out of 0.1. So
[tex]P(A \cap B) = 0.95*0.1 = 0.095[/tex]
What is the probability that a randomly selected person has diabetes, given that his test is positive?
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.095}{0.1013} = 0.9378[/tex]
0.9378 = 93.78% probability that a randomly selected person has diabetes, given that his test is positive.
The table shows a linear function.
Which equation represents the function?
x f(x)
-6 -1
-3 4
0 9
3 14
A. f(x)= -5/3x+9
B. f(x)= -5/3x-9
C. f(x)= 9x+5/3
D. f(x)= 5/3x+9
Answer:
D.
Step-by-step explanation:
Try A:
x = -6, f(x) = -1:-
f(-6) = -5/3(-6) + 9
= 10 + 9 = 19 NOT A.
Try B:
f(-3) = -5/3(-3) - 9
= 5 - 9 = -4 NOT B
Try C:
9(0) + 5/3 = 5/4 NOT C
Try D:
f(3) = 5 + 9 = 14
f(0) = 9, f(-6) = -1 and f(-3) = 4
Given the recursive formula shown, what are the first 4 terms of the sequence?
Answer:
5,20,80,320
Step-by-step explanation:
a1 = 5
an = 4 an-1
Let n = 2
a2 = 4 * a1 = 4*5 = 20
Let n = 3
a3 = 4 * a2 = 4*20 = 80
Let n = 4
a4 = 4 * a3 = 4*80 = 320
Help meee I’ll give 10 pts and brainliest!!!
Step-by-step explanation:
i) [tex]\overline{AB} = \sqrt{(x_A - x_B)^2 + (y_A - y_B)^2}[/tex]
[tex]\:\:\:\:\:\:\:=\sqrt{(2)^2 + (12)^2} = 12.3[/tex]
ii) [tex]m = \dfrac{y_A - y_B}{x_A - x_B} = \dfrac{-12}{2} = -6[/tex]
iii) [tex](\overline{x},\:\overline{y}) = \left(\dfrac{x_A + x_B}{2},\:\dfrac{y_A + y_B}{2}\right)[/tex]
[tex]\:\:\:\:\:\:\:=(3,\:-2)[/tex]
A store spends $10 for each pair of Brand X jeans and adds a 120% markup to the cost. What is the selling price of the jeans? (circle one)
Answer:
12
Step-by-step explanation:
120 divided by 100 =1.2 x 10
Sum of × +1 and × + 2
Step-by-step explanation:
X +1 + X + 2
X + X + 1 + 2
2x + 3
Therefore it's 2x + 3
Write the equation of the line in fully simplified slope-intercept form.
From the graph, we can write that
The equatuon of line passes through (0,4) and
(-8,0) points.
So
[tex] \sf \: slope \: \: m = \frac{4 - 0}{0 - ( - 8)} = \frac{4}{8} = \frac{1}{2} \\ \therefore \green{\sf \: m = \frac{1}{2} }[/tex]
Intercept of Y-axis c = 4
So equation is :
[tex] \bf \: y = mx + c \\ \bf = > y = \frac{1}{2} x + 4 \\ \bf = > 2y = x + 4 \\ \bf= > \orange{ \boxed{ \bf \: x - 2y + 4 = 0}}[/tex]
Please Help! I will give you the brainiest and a lot of points!
a.Use the information given by the graph to determine the truth value of the compound statement. Choose the correct answer below.
b. Write the compound statement's negation. Choose the correct answer below
c. Use the information in the graph to determine the truth value of the negation in part (b). (Is it True or False?)
Answer: TRUE
Step-by-step explanation: THE COMPOUD STATE MEN DETERMEND BY HE GRAPH IS THE SOLUTION AS SAID BY YOU IT IS TRUE BECAUSE THE READINGS ON THE GRAPH SHOW ITS TRUE
