Answer:
The 90% confidence interval for the difference of the population means is approximately (-17.98, -2.02).
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 estabilishes 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.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
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.
Boys:
Mean of 75, sample of 45, standard deviation of 25.
This means that [tex]\mu_B = 75, s_B = \frac{25}{\sqrt{45}}[/tex]
Girls:
Mean of 85, sample of 30, standard deviation of 17.
This means that [tex]\mu_G = 85, s_G = \frac{17}{\sqrt{30}}[/tex]
Distribution of the difference of mean grades of boys and girls:
[tex]\mu = \mu_B - \mu_G = 75 - 85 = -10[/tex]
[tex]s = \sqrt{s_B^2+s_G^2} = \sqrt{(\frac{25}{\sqrt{45}})^2+(\frac{17}{\sqrt{30}})^2} = 4.85[/tex]
Confidence interval:
As stated, the critical value is [tex]z = 1.645[/tex]
The margin of error is of:
[tex]M = zs = 1.645*4.85 = 7.98[/tex]
Lower bound:
[tex]\mu - M = -10 - 7.98 = -17.98[/tex]
Upper bound:
[tex]\mu + M = -10 + 7.98 = -2.02[/tex]
The 90% confidence interval for the difference of the population means is approximately (-17.98, -2.02).
HELP WITH THIS ASAP!
Answer:
Hi, there your answer will C. 85pi ft^2
Step-by-step explanation:
pi(5)(12)+pi(5)^2
60pi+25pi
85pi ft^2
Hope this helps :)
Multiply 4/5 by 10 , and then multiply that product by 17 .
Answer:
your answer is 406.
Step-by-step explanation:
4/5 x 10 will equal to 8. 8 times 17 equals 406.
What does the digit 7 represent in 701, 280?
O Seven hundred
O Seventy thousand
Seven hundred thousand
Seven thousand
Answer: seven hundred thousand
Answer:
The 7 represents the 10,000
Step-by-step explanation:
Its not the hundred because the 2 in 280 is
I need help answering this question please help
A circle has a radius of 4 inches. What is
the circumference?
A.25.12 inches
B.12.56 inches
Answer:
4 x 3.14 x 2 = 25.12 inches
Step-by-step explanation:
Formula of circumference:
3.14(pi) x 2(the number is just always there when finding circumference) x radius(half of your diameter or just your given radius).
Can someone help! This is due right now and I'm a little confused! Thank you!
Answer:
a) 10 cucumbers
b) two fifth x, or 2/5x
c) 15 vegetables
Giving brainliest ; What is the mean of the data set? {20,1,14,14,9,8} Enter your answer in the box.
Answer:
11
Step-by-step explanation:
(20 + 1 + 14 + 14 + 9 + 8) / 6
= 66 / 6
= 11
What is the distance between the points (6, 4) and (-3, 17)?
A) 22
B) √250
C) 125
D) √88
Find the surface area of the following figures.
with solution please. T-T
Answer:
I will do 1 2 3 and 5 for you:
Since a cube has a given length of 5, we know that all sides will be the same therefore your lengths will be the same.
There are 6 sides of a cube so,
5 x 5 = 25 area of one flat surface.
Now 25(an area of one flat surface) x 6(flat surfaces) = 150 cm for question 1
We need to find area of the two circles:
3(given radius)^2(radius being squared) x 3.14(pi)
3 x 3 = 9
9(after radius being squared) x 3.14(pi) = 28.26(area of one circle)
28.26 x 2 = 56.52 (area of 2 circles)
Now we need to find the round surface, but first we need to find circumference:
2 x 3.14 x 3 = 18.84
18.84(circumference) x 5(height) = 94.2 (area of round surface)
Now lets add all the given areas to find surface area:
56.52 + 94.2 = 150.72 cm^2 is your answer for question 2
2 x 4 = 8
8 x 2 = 16
4 x 5 = 20
20 x 2 = 40
2 x 5 = 10
10 x 2 = 20
Add all given areas:
16 + 40 + 20 = 76 cm^2 is your answer for question 3
452.16 cm^2
4 x 3.14 x 6^2
4 x 3.14 x 36 = 452.16 cm^2 is your answer for question 4
8 x 4 = 32, 32 divided by 2 = 16
since there are 4 sides,
4 x 16 = 64
Don't forget the bottom!
4x 4 = 16
Lets add the given areas:
64 + 16 = 80 for question 5
A bank is offering 3.5% simple interest on a savings account. If you earned $525 in interest
in 2 years, how much did you deposit in the savings?
O $7,500
O $8,000
O $7.250
$7.000
Answer:
$7500
Step-by-step explanation:
Given
[tex]I = 525[/tex]
[tex]R = 3.5\%[/tex]
[tex]T =2[/tex]
Required
The Principal
This is calculated using:
[tex]I =PRT[/tex]
Make P the subject
[tex]P = \frac{I}{RT}[/tex]
So, we have:
[tex]P = \frac{525}{3.5\% * 2}[/tex]
[tex]P = \frac{525}{7.0\%}[/tex]
[tex]P = 7500[/tex]
question number nine answer
Answer:9
Step-by-step explanation:
Answer:
I think it's either A or D
Hey luvs!
The endpoints of AB are A(1,4) and B(5,-1). What are the coordinates of the point that divides AB in the ratio
2:3?
Answer:
I don't know I'm sorry.............
no links Pwease help this is very important I will give you brain thing if its correct ♡
Answer:
B, C
Step-by-step explanation:
is 2 a solution to the equation 1/2 x 4 = 5 ?
Answer:
yes it is good luck with your work
The number of red tiles in a sack is 5 more than 3 times the number of green tiles in the sack. The
sack contains 35 red tiles, How many green tiles does the sack contain?
Pls help I need this pls help have a good day
A.12
B.10
C.9
D.not here
Answer:
B. 10
Step-by-step explanation:
10 x 3 = 30+5 = 35
Find the surface area and volume of the figure. Round to the nearest tenth.
write the percent of each figure
that is shaded.
Answer:
1. 21% 2. 70%
Step-by-step explanation:
1. 21 out of 100 are filled in
2. 7/10 are filled in
Based on the stated expectations of the sit-and-reach test, which of the following is TRUE?
A.
Men are generally more flexible than women.
B.
Women are generally more flexible than men.
C.
Men and women are about equally flexible.
D.
No broad conclusions can be drawn about flexibility.
Answer:
B
Step-by-step explanation:
A radioactive substance with initial value of 800g decays according to the exponential model A= 800e^(kt). After 10 years, only 400g of the substance remains. Find the value of k. Round your answer to the nearest thousandth. NO LINKS!!!!
Answer:
k ≈ - 0.069
Step-by-step explanation:
Given
A = 800 [tex]e^{kt}[/tex]
Substitute A = 400 and t = 10 into the equation
400 = 800 [tex]e^{10k}[/tex] ( divide both sides by 800 )
0.5 = [tex]e^{10k}[/tex] ( take the ln of both sides )
ln [tex]e^{10k}[/tex] = ln0.5
10k lne = ln0.5 [ lne = 1 ]
10k = ln 0.5 ( divide both sides by 10 )
k = [tex]\frac{ln0.5}{10}[/tex] ≈ 0.069 ( to the nearest thousandth )
Answer:
Step-by-step explanation:
400 = 800 * e^(k*t)
What are the units of t? I'm taking it as years.
Divide by 800
400/800 = e^(k*10)
1/2 = e^(k*10)
ln(1/2) = ln(e)^(k*10)
ln(1/2) = k*10 * ln(e)
ln(e) = 1
-0.69314 = k*10
-0.069314 = k
Check
A = 800 e^(-0.069314*10)
A = 800 e^(-0.69314)
A = 800 * 0.50000359
A = 400.0028722
Which is close enough to 400
Two parallel lines cut by a transversal are shown. What is the value of X, in degrees?
9514 1404 393
Answer:
x = 15°
Step-by-step explanation:
Same-side interior angles are supplementary.
(4x° +12°) + 108° = 180°
4x° = 60° . . . . . . . . . . . . . . subtract 120°
x = 15° . . . . . . . . . . . . divide by 4
Determine the decision criterion for rejecting the null hypothesis in the given hypothesis test; i.e., describe the values of the test statistic that would result in rejection of the null hypothesis. We wish to compare the means of two populations using paired observations. Suppose that d3.125, 2.911, and n8, and that you wish to test the hypothesis below at the 10% level of significance. What decision rule would you use? : 0 against : 0
Answer:
Decision Rule
The critical region for one tailed test with 7 d.f is t > 1.415 for
H0 : ud ≤ 0 against the claim Ha: ud > 0
Step-by-step explanation:
The data given is
Population mean = ud= 0
Sample difference mean = d`= 3.125
Sample difference standard deviation = sd= 2.911
Sample size= n= 8
Formulate the null and alternate hypotheses as
H0 : ud ≤ 0 against the claim Ha: ud>0
The significance level ∝= 0.1
The degrees of freedom = n-1 = 8-1 = 7
The critical region for one tailed test with 7 d.f is t > 1.415
The test statistic is
t= d`- ud/ sd/ √n
Putting the values
t= 3.125-0 / 2.911/√8
t= 3.125/1.0292
t= 3.036
since the calculated value of t falls in the critical region we reject the null hypothesis .
Jovi distributed 3(n+2) and got 3 x n + 3 x 6 is his answer correct
Answer:
Step-by-step explanation:
since 3 is outside the parenthesis (n + 2) you multiply the 3 by the n and the 2 and
3n + 6
next subtract the 6 and add the 6 to the other side
3n - 6 = 6
3n = 6
n = 2
100 POINTS!!!!!! HELP
Question 23
Max and Jay are among 12 contestants in the school spelling bee. If the top two finishers win prizes, what is the probability both Max and Jay will be the two prize winners?
A
1766
B
136
C
166
D
1132
Find the distance of the two given points (1,5) and (4,10)
Answer:
5.831
Step-by-step explanation:
Distance between both given points=Lenght=5.831
Qu
Peter hired a cleaning company to clean his house. The cleaning company charges a
fixed fee of $15 plus $17 per hour to clean a house.
a. Write an equation that can be used to determine, c, the total amount in dollars that
the cleaning company charges to clean a house in h hours.
To find the total cost you need to multiply the hourly rate by the number of hours they work and add the fixed fee.
C = 17h + 15
How do the angles and side lengths of the preimage relate to the corresponding angles and side lengths of the image of a dilation with a scale factor not equal to 1?
Answer:
The angles are proportional and the side lengths are proportional.
Step-by-step explanation:
Savaas Realize
I will go potty now thx
A bag contains eight white marbles, six red marbles and four blue marbles.
How many blue marbles must be added to the bag so that the probability
of choosing a blue marble is 1/2?
a. 6
b. 5
c. 10
d. 0
Answer:
c) 10
Step-by-step explanation:
you need to add the white and red marbles which would be 14.
then you subtract 14 by the amount of blue marbles.
HELP ME PLEASEEEEEEEEEEEEEEEEEEE
Answer:
The second answer choice
Step-by-step explanation:
The pyramid shown is a triangular pyramid. A triangular pyramid consist of 4 faces; 1 triangular base and 3 triangular lateral faces.
Hence, the correct answer would be the second choice.
2. Use the image to answer the questions.
(a) What is the center and the radius of the circle?
(b) What are the equations of the circle in graphing form and in general form? Show your work.
Answer:
Center = (-1, 1)
Radius = 3
Graphing form
(x + 1)² + (y - 1)² = 3²
General form
x² + y² + 2x - 2y - 7 = 0
Step-by-step explanation:
Center = (-1, 1)
Radius = 3
Graphing form
(x + 1)² + (y - 1)² = 3²
General form \Expand graphing form\
(x² + 2x + 1) + (y² - 2y + 1) - 9 = 0
Rearrange
x² + y² + 2x - 2y - 7 = 0