At a large Midwestern university, a simple random sample of 100 entering freshmen in 1993 found that 20 of the sampled freshmen finished in the bottom third of their high school class. Admission standards at the university were tightened in 1995. In 1997, a simple random sample of 100 entering freshmen found that only 10 finished in the bottom third of their high school class. Let p 1 and p 2 be the proportions of all entering freshmen in 1993 and 1997, respectively, who graduated in the bottom third of their high school class. What is a 90% plus four confidence interval for p 1 – p 2?

Answers

Answer 1

Answer:

The 90% confidence interval for the difference of proportions is (0.01775,0.18225).

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.

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.

p1 -> 1993

20 out of 100, so:

[tex]p_1 = \frac{20}{100} = 0.2[/tex]

[tex]s_1 = \sqrt{\frac{0.2*0.8}{100}} = 0.04[/tex]

p2 -> 1997

10 out of 100, so:

[tex]p_2 = \frac{10}{100} = 0.1[/tex]

[tex]s_2 = \sqrt{\frac{0.1*0.9}{100}} = 0.03[/tex]

Distribution of p1 – p2:

[tex]p = p_1 - p_2 = 0.2 - 0.1 = 0.1[/tex]

[tex]s = \sqrt{s_1^2+s_2^2} = \sqrt{0.04^2 + 0.03^2} = 0.05[/tex]

Confidence interval:

[tex]p \pm zs[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

90% confidence level

So [tex]\alpha = 0.1[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.1}{2} = 0.95[/tex], so [tex]Z = 1.645[/tex].  

The lower bound of the interval is:

[tex]p - zs = 0.1 - 1.645*0.05 = 0.01775 [/tex]

The upper bound of the interval is:

[tex]p + zs = 0.1 + 1.645*0.05 = 0.18225 [/tex]

The 90% confidence interval for the difference of proportions is (0.01775,0.18225).


Related Questions

Given the sequence 4, 8, 16, 32, 64, ..., find the explicit formula.

Answers

128Answer:

128

Step-by-step explanation:

vì 4+4=8

8+8=16

16+16=32

32+32=64

64+64=128

Help please im new and i need help

Answers

9514 1404 393

Answer:

  B) False

Step-by-step explanation:

Triangles are similar when their angles are the same measures. Because the angles sum to 180°, we only need to show that 2 angles of one triangle are equal to 2 angles of the other triangle.

All three of the angles of the first triangle are given: 20°, 40°, 120°.

One of the angles of the second triangle matches: 40°; but the other angle (80°) doesn't match either of 20° or 120°.

The angles aren't the same, so the triangles are not similar.

__

If we want to go to the trouble, we can figure the third angle of the second triangle. It is 180° -40° -80° = 60°.

Then the angles in the two triangles, listed smallest to largest, are ...

  20°, 40°, 120°

  40°, 60°, 80°

It is clear the angles of these triangles are not the same.

According to the video, this career offers a good opportunity to do what?
O supervise other workers
O learn an employer's business
Obecome physically fit
Obuild friendships with customers

Answers

Answer:

The correct answer is "learn an employers business"

Step-by-step explanation:

Supervising other workers isn't their job

Becoming physically fit wouldn't help them with that job

Building friendships with customers isn't part of the job

According to the video, this career offers a good opportunity to learn an employer's business. Therefore, the correct option is option B.

What is career?

There are two definitions of a career. It's common to use the word "career" to describe a profession, occupation, trade, or vocation. The work you perform for a livelihood is defined by your job, which can range from occupations requiring substantial education and training to ones that can be performed using a high school certificate and then a desire to gain knowledge.

Work as a doctor, attorney, teacher, carpenter, veterinarian assistant, electrician, cashier, instructor, or hairstylist is an example of a career. According to the video, this career offers a good opportunity to learn an employer's business.

Therefore, the correct option is option B.

To know more about career, here:

https://brainly.com/question/30104104

#SPJ6

The line perpendicular to y=3/4x+7 containing (3,-4)

Answers

Answer:

y = - [tex]\frac{4}{3}[/tex] x

Step-by-step explanation:

1). [tex]y_{1}[/tex] = [tex]m_{1}[/tex] [tex]x_{1}[/tex] + [tex]b_{1}[/tex]  

[tex]y_{2}[/tex] = [tex]m_{2}[/tex] [tex]x_{2}[/tex] + [tex]b_{2}[/tex]

[tex]y_{1}[/tex] ⊥ [tex]y_{2}[/tex]  if  [tex]m_{2}[/tex] = - [tex]\frac{1}{m_{1} }[/tex]

2). ( [tex]x_{3}[/tex] , [tex]y_{3}[/tex] )

y - [tex]y_{3}[/tex] = m( x - [tex]x_{3}[/tex] )

~~~~~~~~~~~~~~~~~~

y = [tex]\frac{3}{4}[/tex] x + 7

[tex]m_{1}[/tex] = [tex]\frac{3}{4}[/tex]

[tex]m_{2}[/tex] = - [tex]\frac{4}{3}[/tex]

( 3, - 4 )

y - ( - 4) = - [tex]\frac{4}{3}[/tex] ( x - 3 )

y + 4 = - [tex]\frac{4}{3}[/tex] x + 4

y = - [tex]\frac{4}{3}[/tex] x

How many real solutions does this system of equations have? x2 +3 = y
3х — у+1 = 0

Answers

Answer:

Step-by-step explanation:

y = x²+3

y = 3x+1

x² + 3 = 3x +1

x² - 3x + 2 = 0

(x-2)(x-1) = 0

x = 2, 1

Two solutions

(2,7) and (1,4)

3)
Write an inequality for the graph below. If necessary, use
<= for < or >= for.



Kinda stuck and running out of time

Answers

Answer:

Step-by-step explanation:

PLEASE HELP

-6/5k=12

Show your work in details if you can, I have a hard time understanding this.

Answers

[tex]\begin{cases}\large\bf{\green{ \implies}} \tt \: - \frac{6}{5} \: k \: = \: 12 \\ \\ \large\bf{\green{ \implies}} \tt \: - \frac{6k}{5} \: = \: 12 \\ \\ \large\bf{\green{ \implies}} \tt \: - 6k \: = \: 12 \: \times \: 5 \\ \\ \large\bf{\green{ \implies}} \tt \: - 6k \: = \: 60 \\ \\ \large\bf{\green{ \implies}} \tt \: k \: = \: \cancel\frac{60}{ - 6} \\ \\ \large\bf{\green{ \implies}} \tt \: k \: = \: - 10 \end{cases}[/tex]

K=-12 that is the answer hope it helps

how do you change a hot air baloon descends 200 feet per minute from a altitude of 1000 feet into a algebraic expression.

Answers

y = 1000-200x where x is the number of minutes and y is the altitude of the balloon

In a certain year Congress debated a bill. A poll of 1000 Americans indicated 401 opposed 293 favored 306 not sure. What is the probability that random person was in favor

Answers

So actually you have 100%
401 + 239 + 306 = 1000

Now 293 from the 1000 is favored,
So in pregnant is 293/1000 = 0.293
That’s also the probability to random person is favor (or 29.3% chance)

There is a language with 12 distinct letters. How many words that are less than four letters long can possibly be formed? (Assume any combination of letters is valid and letters can be repeated). Can you help me out with this one?

Answers

Answer:

1884

Step-by-step explanation:

1)If you hear the condition "less than four letters" it means that each word can consist of 3,2 or 1 letter. Firstly, consider the easiest situation with the word from one letter. There are 12 letters, so there are 12 words from one letter.

Then the words from two letters. The first letter of such a word can be chosen in 12 means(because 12 letters are available), then the second letter can be chosen in 12 means too. 12*12=144 words with 2 letters. (Multiplying, not adding, because each two words form one combination).

Then for the words from three letters, use the same rule, 12 means for the first letter, 12 means for the second letter, 12 means for the third letter. 12*12*12=1728 words.

Having particular words from 1,2,3 letters add them to get total quantity of words: 12+144+1728=1884words,that is the answer.

Please help urgently

Answers

Answer:

Explanation:

Prove that triangle PQS is congruent to triangle RSQ

PS = QR (given)
PQ = RS (given)
Angle PQS = Angle QSA

Therefore, triangle PQS and triangle QSA is congruent (SAS).

Hi I need help :( I can’t figure these out

Answers

Step-by-step explanation:

I do don't either ok wjshjddshsj

Answer:

Part A: A scatter diagram (Also known as scatter plot, scatter graph, and correlation chart) is a tool for analyzing relationships between two variables for determining how closely the two variables are related. One variable is plotted on the horizontal axis and the other is plotted on the vertical axis. The dots in a scatter plot not only report the values of individual data points, but also patterns when the data are taken as a whole. Identification of correlational relationships are common with scatter plots.

Part B: There are three types of correlation: positive, negative, and none (no correlation).

Part C: A scatter plot is a graph of points that show the relationship between two different pieces of data, while a line graph is a graph that shows information via a connected line.

Please mark me brainliest:))

Which inequality is true?
O A. 1 2 > 2
OB. 8 - T > 5
O C. 1071 > 30
O D. 1+4<7

Answers

Answer:

true

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

A

[tex]\frac{12}{2\pi }[/tex]  ≈ 1.91 < 2

B

8 - π 8 - 3.14 = 4.86 < 5

C

10π ≈ 31.42 > 30 ← True

D

π + 4 = 3.14 + 4 = 7.14 > 7

Option C is a true inequality

find the value of the trigonometric ratio. make sure to simplify the fraction if needed

Answers

Answer:

12/5

Step-by-step explanation:

since we are dealing with the angle at Z, we consider Z also to be the center of a circle.

then 10 is the radius of this circle.

24 is tan Z in this circle with radius 10.

tan Z in the standard circle with radius 1 is simply 1/10 of the tan Z in the circle with radius 10.

so, tan Z = 24/10 = 12/5

Tina invests $3,700 into an account with a 4.4% interest that is compounded quarterly. How much money will she have in
this account if she keeps it for 8 years?
Round your answer to the nearest cent.
Do NOT round until you have calculated the final answer.

Answers

Answer:

bacoot anjing

lo siapa hah kan bisa jawab sendiri sok sok minta bantuuuu

Step-by-step explanation:

maluiiin

Answer:

$5250.96

Step-by-step explanation:

Future value= Present value(1+r)^n

=3700(1+0.011)^32

r=4.4÷100÷4

n=8×4

A scientist is studying the growth and development of an epidemic virus with a growth rate of 9% per month that has infected 3,124 people. If this rate continues, what will be the number of infected people in another 9 months? Round your answer to the nearest whole number.

Answers

Answer:

About 6,785 people will be infected about nine months.

Step-by-step explanation:

We can write an exponential function to represent the situation. The standard exponential function is given by:

[tex]\displaystyle f(x) = a(r)^x[/tex]

Where a is the initial value, r is the rate, and x, in this case, is the time that has passed in months.

3,124 people have already been infected. Thus, our initial value a = 3124.

And an additional 9% will be infected per month. Therefore, our rate r will be 1 + 9% or 1.09.

Hence, our function is:

[tex]\displaystyle f(x) = 3124(1.09)^x[/tex]

Then after nine months, the total amount of infected people will be f(9):

[tex]\displaystyle f(9) = 3124(1.09)^{(9)}[/tex]

Use a calculator:

[tex]\displaystyle f(9) \approx 6785[/tex]

About 6,785 people will be infected about nine months.

Answer:

7,022

Step-by-step explanation:

Given:
AD
diameter of Circle P.
Dec
B
A
If m < 1 = 30°, then m AB
15
30
60

Answers

Answer:

The measure of an arc is the size of the corresponding central angle, so angle 1 for AB,

Answer: B 30

Will give brainliest answer

Answers

Answer:

Step-by-step explanation:

A(1) is the amount after 1 decade.

A(0.1) is the amount after 1  year.

Every year, the amount of CO₂ increases by a factor of 1.06^(0.1) ≅ 1.0058

Do this please helpppp

Answers

Answer:

y = [tex]\frac{20}{9}[/tex]

Step-by-step explanation:

Since the figures are similar then the corresponding sides are in proportion, that is

[tex]\frac{JH}{PQ}[/tex] = [tex]\frac{FM}{ST}[/tex] , substitute values

[tex]\frac{6}{4}[/tex] = [tex]\frac{7}{3y-2}[/tex] ( cross- multiply )

6(3y - 2) = 28

18y - 12 = 28 ( add 12 to both sides )

18y = 40 ( divide both sides by 18 )

y = [tex]\frac{40}{18}[/tex] = [tex]\frac{20}{9}[/tex]

Answer:

20/9

Step-by-step explanation:

since the 2 are similar,

JH/PQ = FM/ST

6/4 = 7/(3y-2)

6(3y-2) = 7*4

18y-12=28

18y = 40

y = 40/18 = 20/9 = 2 2/9

Lesson 9.6: Steady-State Analysis.) Consider a particular data set of 100,000 stationary waiting times obtained from a large queueing system. Suppose your goal is to get a confidence interval for the unknown mean. Would you rather use (a) 50 batches of 2000 observations or (b) 10000 batches of 10 observations each?

Answers

Answer:

I would rather use:

(b) 10,000 batches of 10 observations each.

Step-by-step explanation:

It is easier to have 10,000 batches of 10 observations each than to have 50 batches of 2,000 observations.  Human errors are reduced with fewer observations. For example, Hadoop, a framework used for storing and processing big data, relies on batch processing.  Using batch processing that divides the 100,000 stationary waiting times into 10 observations with 10,000 batches each is more efficient than having 2,000 observations with 50 batches each.

solve similar triangles (advanced)
solve for x

Answers

Answer:

27/2 =x

Step-by-step explanation:

We can write a ratio to solve

3             2

-----  = ---------

3+x          11

Using cross products

3*11 = 2(3+x)

33 = 6+2x

Subtract 6 from each side

33-6 = 6+2x-6

27 = 2x

27/2 = 2x/2

27/2 =x

10 times as much as 9

Answers

Answer:

90

Step-by-step explanation:

10 x 9

=> 90

10 times 9 is 90.

find x in the following​

Answers

Answer:

i. ans in picture

ii. ans in picture

iii. ans in picture

iv. 19

v. 38

Step-by-step explanation:

i. working in picture

ii. working in picture

iii. working in picture

iv.

180-90=90

90=2x+7+45=2x+52

2x=90-52=38

x=19

v.

angle COD=3x+10

180-3x+10-2x

180+10=2x+3x

190=5x

x=38

Answer:

x = 123- 56=67x= 17x=125x=19x= 20

Step-by-step explanation:

Apply the following triangle laws:

The sum of the angles of a triangle will always be 180 degrees.

find the measure of the angle indicated

Answers

Answer:

Step-by-step explanation:

59°

Multiply:

2 × (–21) × 7


A)

294

B)

–273

C)

–7

D)

–294

Answers

Answer:

[tex]2\times \left(-21\right)\times \:7[/tex]

PEMDAS order of operations:

[tex]2\times \left(-21\right)=-2\times \:21=-42[/tex]

[tex]=-42\times \:7[/tex]

[tex]=-294[/tex]

D) -294 is your answer

OAmalOHopeO

Use pemdas order & that’ll get you to your answer which is D) -294

What is the minimum perimeter of a rectangle with an area of 625 mm^2

Answers

130 mm^2 your welcome

if I have to add 97 oz of algaecide to 10,000 gallons of water how much should I add if I only have 200 gallons of water​

Answers

Answer:

1.94 oz

Step-by-step explanation:

x/97 = 200/10000

97*200 = 10,000x

19400 = 10,000x

1.94 oz

You can also do it this way:

200/10000 = 0.02

0.02 * 97 = 1.94

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

There are 25 peanut candies in a bowl. 4 red, 3 orange, 4 yellow, 5 green, 6 blue and 3 brown. what is the probability of randomly choosing a blue candy from the bowl?​

Answers

Answer:

6/25  or 24%

Step-by-step explanation:

Answer:

6/25, 0.24, or 24% chance

Step-by-step explanation:

Hi there!

We're given that:

⇒ There are 25 peanut candies in total

⇒ 6 out of the 25 candies are blue

To find the probability of randomly choosing a blue candy from the bowl, divide 6 by 25:

6/25 = 0.24 = 24%

I hope this helps!

Determine the dimension of the vector space. M4,2
STEP 1: Determine the number of linearly independent vectors needed to span M4,2. The basis for M4,2 has linearly independent vectors.
STEP 2: Using the result from Step 1, determine the dimension of M4,2.

Answers

Answer:  

STEP 1  

M_{4,2} is set of 4x2 matrices hence each matrix has 4*2=8 entries. Each entry can be filled independently.  

Hence its basis has 8 linearly independent vectors.  

STEP 2  

Dimension= cardinality of basis = 8.

How much state tax is withheld from $36,200 if the tax rate is 4%?

Answers

Answer:

$1448

Step-by-step explanation:

Tax=rate*amount=(4/100)*36200=1448

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