In the past, 19% of all homes with a stay-at-home parent had the father as the stay-at-home parent. An independent research firm has been charged with conducting a sample survey to obtain more current information. (a) What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.03? Use a 95% confidence level. (Round your answer up to the nearest whole number.)
Answer:
A sample size of 657 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which
z is the zscore that has a pvalue of [tex]1 - \frac{\alpha}{2}[/tex].
The margin of error is:
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
95% confidence level
So [tex]\alpha = 0.05[/tex], z is the value of Z that has a pvalue of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].
In the past, 19% of all homes with a stay-at-home parent had the father as the stay-at-home parent.
This means that [tex]\pi = 0.19[/tex]
(a) What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.03?
A sample size of n is needed.
n is found when [tex]M = 0.03[/tex]
Then
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
[tex]0.03 = 1.96\sqrt{\frac{0.19*0.81}{n}}[/tex]
[tex]0.03\sqrt{n} = 1.96\sqrt{0.19*0.81}[/tex]
[tex]\sqrt{n} = \frac{1.96\sqrt{0.19*0.81}}{0.03}[/tex]
[tex](\sqrt{n})^{2} = (\frac{1.96\sqrt{0.19*0.81}}{0.03})^{2}[/tex]
[tex]n = 656.91[/tex]
Rounding up to the nearest whole number.
A sample size of 657 is needed.
Ms Davis is doing an activity with her statistic students where she gives them a 20 question multiple top choice test and they know none of the answers. Students need to guess on every question and each question has 5 possible choices, 1 of the which is correct.
What is the mean and standard deviation of the number of questions that each student gets correct?
Answer:
The mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.
Step-by-step explanation:
Let the random variable X be defined as the number of correct answers marked by a student.
It is provided that each question has 5 possible choices, 1 of the which is correct.
Then the probability of marking thee correct option is:
[tex]P(X)=\frac{1}{5}=0.20[/tex]
There are a total of n = 20 questions to be answered.
As the students does not the answer to any question, they would be guessing for each question. This implies that for a random question, all the five options has the equal probability of being correct and each of the five options can be correct independently from the other.
All these information above indicates that the random variable X follows a Binomial distribution with parameters n = 20 and p = 0.20.
The mean and standard deviation of a Binomial distribution are:
[tex]\mu=np\\\\\sigma=\sqrt{np(1-p)}[/tex]
Compute the mean and standard deviation of the random variable X as follows:
[tex]\mu=np=20\times 0.20=4\\\\\sigma=\sqrt{np(1-p)}=\sqrt{20\times 0.20\times(1-0.20)}=1.789[/tex]
Thus, the mean and standard deviation of the number of questions that each student gets correct are 4 and 1.789 respectively.
According to the question,
The probability of making 3 correct options will be:
→ [tex]P(X) = \frac{1}{5}[/tex]
[tex]= 0.20[/tex]
Total number of questions,
n = 20As we know,
The mean will be:
→ [tex]\mu = np[/tex]
By substituting the values, we get
[tex]= 20\times 0.20[/tex]
[tex]= 4[/tex]
and,
The standard deviation will be:
→ [tex]\sigma = \sqrt{np(1-p)}[/tex]
[tex]= \sqrt{20\times 0.20\times (1-0.20)}[/tex]
[tex]= 1.789[/tex]
Thus the responses above are correct.
Learn more about standard deviation here:
https://brainly.com/question/20896613
Rewrite the percentage in the sentence below as a decimal.
The 20 overseas investors own 7.2% of the business.
Answer:
0.072
Step-by-step explanation:
Answer:0.072
Step-by-step explanation:
7.2% = 7.2/100
7.2 ➗ 100=0.072
Which fraction equals a repeating decimal?
30/50
13/25
5/30
13/10
Answer:
5/30
Step-by-step explanation:
5/30 = 1/6 =0.166666666...
The fraction equals a repeating decimal is 5/30.
What are decimals?A decimal numeral system is the standard system for denoting integer and non-integer numbers. The way of denoting numbers in the decimal system is often referred to as decimal notation.
Now the given fractions are,
30/50
13/25
5/30
13/10
Converting them into decimals we get,
30/50 = 0.6
13/25 = 0.52
5/30 = 0.1666..
13/10 = 1.3
Thus the repeating decimal is 0.1666..
So, the fraction with repeating decimal is 5/30 = 0.1666..
Thus, the fraction equals a repeating decimal is 5/30.
To learn more about fraction :
brainly.com/question/1301963
#SPJ2
A sphere is inscribed in a cube. Explain the relationship between the surface areas of the two solid figures
Answer:
No one knows. Jk just go look at the other brainly links. the question has already been asked and answered so you can go see them there.
Step-by-step explanation:
:)
The circle graph shows how Spencer spent his money in the month of July.
A circle graph representing Spencers expenses. 27 percent is clothing, 11 percent is Gasoline, 44 percent is Food and 18 percent is Entertainment.
Part A
If Spencer spent a total of $704.00 in the month of July, which is the best estimate for the amount of money he spent on clothing?
$70.00
$140.00
$210.00
$280.00
00:00
Part B
Which is the best estimate for the amount of money he spent on entertainment?
$140.00
$35.00
$105.00
$160.00
Answer:
$190.08
Step-by-step explanation:
Take 27% of the total $704 spent in July:
0.27($704) = $190.08
He spent an estimated $190.08 on clothing in July.
Answer:
Step-by-step explanation:
I THINK 140
Trisomy 18 (T18) is a rare genetic disorder that severely disrupts a baby's development prior to birth. Many die before birth and most die before their first birthday. T18 occurs in only 1 in 2500 pregnancies in the U.S. A genetic test on the mother's blood can be done to test for T18 in her baby. The overall probability of a positive test result is 0.010384. The probability of a positive test result for a baby with T18 is 0.97. The probability of a negative test result for a baby without T18 is 0.99. A mother's blood tests positive for T18. What is the probability that her baby has T18
Answer:
3.74% probability that her baby has T18
Step-by-step explanation:
Bayes Theorem:
Two events, A and B.
[tex]P(B|A) = \frac{P(B)*P(A|B)}{P(A)}[/tex]
In which P(B|A) is the probability of B happening when A has happened and P(A|B) is the probability of A happening when B has happened.
In this question:
Event A: Positive test.
Event B: The baby having T18.
T18 occurs in only 1 in 2500 pregnancies in the U.S.
This means that [tex]P(B) = \frac{1}{2500} = 0.0004[/tex]
The probability of a positive test result for a baby with T18 is 0.97.
This means that [tex]P(A|B) = 0.97[/tex]
The overall probability of a positive test result is 0.010384.
This means that [tex]P(A) = 0.010384[/tex]
What is the probability that her baby has T18
[tex]P(B|A) = \frac{0.0004*0.97}{0.010384} = 0.0374[/tex]
3.74% probability that her baby has T18
Carpetland carpet installers incur an average cost of $300 for each carpet installed. Joan Chin, the firm’s vice president, proposes a new procedure for installations, which she hopes will be more efficient. Joan plans to run a trial and hopes that the results of a trial period will enable her to conclude with a level of significance of 0.05 that the new procedure reduces the average cost to install a carpet. If Joan's hypothesis test results in a Type II error, what would this mean?
Answer:
A Type II error happens when the null hypothesis failed to be rejected, although it is false and the alternative hypothesis is true.
In this context, would be that the test does not give enough evidence to support the claim that the new procedure reduces the average cost, although it really does reduces it.
The new procedure is effective, but the sample does not give enough evidence.
Step-by-step explanation:
Please help ASAP! I will mark Brainliest! Please READ the question THEN answer CORRECTLY! No guessing!
Answer:
C. [tex]\frac{\sqrt{5} }{8}[/tex]
Step-by-step explanation:
This expression can be rewritten as [tex]\frac{\sqrt{5} }{\sqrt{64} }[/tex].
Since the square root of 5 is prime and does not have any perfect square factors, it cannot be simplified. However, the square root of 64 is equal to 8, so our final simplified radical expression would be [tex]\frac{\sqrt{5} }{8}[/tex], which is option C.
HOPE THIS HELPED! :)
Answer:
C is the answer
Step-by-step explanation:
You have to rewrite as [tex]\sqrt{5}[/tex]/[tex]\sqrt{64}[/tex]. Then you have to simplify the denominator which is 8. That is how you get your answer.
Hope this helps.
If u(x)=-2x^2+3 and v(x)=1/x, what is the range of (uov)(x)
Answer:
Do my question i will do yours
Step-by-step explanation:
Answer:
The Answer is C
Step-by-step explanation:
the midpoint of AB is point P at (-16,6) if point A is at (-10,8) what are the coordinates of point B?
Answer:
Denote B(x, y), we have:
-10 + x = 2 x (-16) => x = -22
8 + y = 2 x 6 => y = 4
=> B(-22, 4)
Hope this helps!
:)
The sum of the measures of the angles of a triangle is 180. The sum of the measures of the second and third angles is five times the measure of the first angle. The third angle is 14 more than the second. Let x, y, and z represent the measures of the first, second, and third angles, respectively. Find the measures of the three angles.
Answer:
[tex]x=30\\y=68\\z=82[/tex]
Step-by-step explanation:
x = measure of the first angle
y = measure of the second angle
z = measure of the third angle
The sum of the measures of the second and third (y+z) is five times the measure of the first angle (=5x)
[tex]y+z=5x[/tex]
The third angle is 14 more than the second
[tex]z=y+14[/tex]
And remember that the sum of these three angles must be equal to 180.
[tex]x+y+z=180[/tex]
Let's take these equations
[tex]y+z=5x\\z=y+14\\x+y+z=180[/tex]
If you take a look at the first equation, we have y+z = 5x and we have y+z in the third equation as well, we can replace that....
[tex]x+y+z=180\\x+(y+z)=180\\x+(5x)=180[/tex]
Distribute the + sign
[tex]x+5x=180[/tex]
Combine like terms;
[tex]6x=180[/tex]
Divide by 6.
[tex]x=\frac{180}{6}\\ x=30[/tex]
We have now defined that the measure of the first angle is 30º.
Let's take another equation... for example [tex]z=y+14[/tex]
I'm going to take this one because if I replace x and z in the third equation, all I'll have left will be y.
[tex]x+y+z=180\\30+y+(y+14)=180[/tex]
Distribute the + sign and Combine like terms;
[tex]30+y+y+14=180\\44+2y=180\\[/tex]
Subtract 44 to isolate 2y.
[tex]2y=180-44\\2y=136[/tex]
Now divide by 2.
[tex]y=\frac{136}{2}\\ y=68[/tex]
We already have the value of x and y. Once again, replacing this in the third equation will leave us with z to solve for.
[tex]x+y+z=180\\30+68+z=180\\98+z=180\\z=180-98\\z=82[/tex]
€1.4 m
1.9 m
Tim has to cover 3 tanks completely with paint.
Each tank is in the shape of a cylinder with a top and a bottom.
The tank has a diameter of 1.4 metres and a height of 1.9 m.
A tin of paint covers 5 m
Find the total surface area of the 3 tanks and state how
many tins of paint Tim will need to buy
You must show your working
Total marks 5
Answer:
Step-by-step explanation:
Since each tank is cylindrical, we would apply the formula for determining the total surface area of a cylinder which is expressed as
Total surface area = 2πr² + 2πrh
Where
r represents the height of the cylinder.
h represents the height of the cylinder.
π = 3.14
From the information given,
Height = 1.9
Diameter = 1.4
Radius = diameter/2 = 1.4/2 = 0.7
Total surface area = 2 × 3.14 × 0.7² + 2 × 3.14 × 0.7 × 1.9 = 3.0772 + 8.3524 = 11.4296 m²
Total surface area of the 3 cylinders = 11.4296 × 3 = 34.29 m²
Since a tin of paint covers 5 m², the number of tins paints that Tim will need to buy is
34.29/5 = 6.858
Since the tins of paint must be whole numbers, he needs to buy 7 tins of paints.
Priscilla’s grandmother’s fruit salad recipe calls for one part apple, one part orange, four parts strawberry, two parts cherry, and three parts grape. Priscilla uses the same measuring cup to measure all of the fruit, so one part is equal to one cup of diced fruit. In this exercise, you will compare the quantities in the recipe to understand ratios better.
Answer:
There are 11 parts of fruit: 4-strawberry, 3- grape, 2, cherry, 1- apple, 1-orange 4/11 from the entine quantity of fruits- strawberry
3/11-grapes
2/11- cherries
1/11- apples
1/11- oranges } ⇒ the quantity of oranges and apples are equal Hope it helps ;>
Consider the graph of the exponential function, y =3(2)^x. The x- intercept of the graph is
Answer:
the x intercept is 2
Step-by-step explanation:
I just went over this unit
Answer:
2
Step-by-step explanation:
Please help ASAP! I will mark Brainliest! Please answer CORRECTLY! No guessing!
Answer:
Option D: 5591.93
Step-by-step explanation:
The best way to understand this question is to apply the formula in an indirect manner;
P - Principle number, Starting Value
T - Time
I - Interest
Let us convert the interest into decimal form, such that 3.8% is shifted two decimal points to the right ⇒ 0.038. Now add 1 to this value to get ⇒ 1.038. By PEDMAS, you would first raise this value to the span of 3 years as such:
(1.038)^3 = 1.118386872.......
The final step would by to multiply the starting value (investment $) $ 5,000 by this continuing value of 1.118386872:
5,000(1.118386872) = 5591.93436 ⇒ Rounded to (About) 5591.93
Answer:D
Step-by-step explanation:
principal=p=$5000
Rate=r=3.8%
Time=n=3 years
amount=a
a=p(1+r/100)^n
a=5000(1+3.8/100)^3
a=5000(1+0.038)^3
a=5000(1.038)^3
a=5000 x 1.038 x 1.038 x 1.038
a=5591.93
a=$5591.93
What is the volume of a cylinder with a base radius of 4 and height 7?
Answer:
351.86
Step-by-step explanation:
Points X( -6, -4), Y( -2, -8), Z( 2,-4) are the vertices of a right triangle. What is the area of XYZ? Round to the nearest tenth.
Answer:
16
Step-by-step explanation:
distance between point x and z is 8 units
distance between point z and y is 4 units
8 * 4 = 32
formula for area of a triangle (l * w)/2
plugin: (8 * 4)/2 = 16
The management of Discount Furniture, a chain of discount furniture stores in the Northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 salespeople were selected at random, and their weekly incomes before and after the plan were recorded. Was there a significant increase in the typical salesperson’s weekly income due to the innovative incentive plan? Use the .05 significance level. Estimate the p-value, and interpret it
Answer:
Step-by-step explanation:
The question is incomplete. The complete question is
The management of Discount Furniture, a chain of discount furniture stores in the Northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 salespeople were selected at random, and their weekly incomes before and after the plan were recorded.
Salesperson Before After
Sid Mahone $320 $340
Carol Quick 290 285
Tom Jackson 421 475
Andy Jones 510 510
Jean Sloan 210 210
Jack Walker 402 500
Peg Mancuso 625 631
Anita Loma 560 560
John Cuso 360 365
Carl Utz 431 431
A. S. Kushner 506 525
Fern Lawton 505 619
Solution:
Corresponding income of salespersons before and after form matched pairs.
The data for the test are the differences between the income is salespersons.
μd = the income before minus their income after.
Bedore after diff
320 340 -20
290 285 5
421 475 - 54
510 510 0
210 210 0
402 500 - 98
625 631 -6
569 560 0
360 365 - 5
431 431 0
506 525 - 19
505 619 - 114
Sample mean, xd
= (- 20 + 5 - 54 + 0 + 0 - 98 - 6 + 0 - 5 + 0 + - 19 - 114)/12 = - 25.92
xd = - 25.92
Standard deviation = √(summation(x - mean)²/n
n = 12
Summation(x - mean)² = (- 20 + 25.92)^2 + (5 - 25.92)^2 + (- 54 + 25.92)^2+ (0 + 25.92)^2 + (0 + 25.92)^2 + ( - 98 + 25.92)^2 + ( - 6 + 25.92)^2 + (0 + 25.92)^2 + (- 5 + 25.92)^2 + (0 + 25.92)^2 + (- 19 + 25.92)^2 + (- 114 + 25.92)^2 = 17784.5168
Standard deviation = √(17784.5168/12
sd = 38.5
For the null hypothesis
H0: μd ≥ 0
For the alternative hypothesis
H1: μd < 0
1) The distribution is a students t. Therefore, degree of freedom, df = n - 1 = 12 - 1 = 11
2) The formula for determining the test statistic is
t = (xd - μd)/(sd/√n)
t = ( - 25.92- 0)/(38.5/√12)
t = - 2.33
3) We would determine the probability value by using the t test calculator.
p = 0.02
4) Assume alpha = 0.05
Since alpha, 0.05 > than the p value, 0.02, then we would reject the null hypothesis. We can conclude that at 5% significance level, there is a significant increase in the typical salesperson’s weekly income due to the innovative incentive plan
How many boys are there in an introductory geology course if 360 students are enrolled and there are five boys to every seven girls?
Answer:150 branliest
Step-by-step explanation:
Answer:
150
Step-by-step explanation:
360/(5+7)=30
30*5=150
Writing Percents as Fractions
a. Write 35% as a fraction in simplest form.
35% =
35
100
Write as a fraction with
a denominator of 100.
7
20
Simplity.
Answer:
Answers are below
Step-by-step explanation:
Percent means "out of 100" so 35% is 35/100. We can simplify this fraction by dividing the numerator and denominator by 5. 35/100 / 5 = 7/20.
7/20 multiply the numerator and denominator by 5.
7/20 x 5 = 35/100
If this answer is correct, please make me Brainliest!
Answer:
b and c
Step-by-step explanation:
A bag contains 10 Yellow, 4 Green and 7 Blue marbles. Find the following probabilies.
P(blue)
Answer:
1/3
Step-by-step explanation:
The total number of marbles
10+4+7 = 21
P(blue) = blue marbles / total marbles
= 7 / 21
= 1/3
what is this phrase in numerical expression
triple the sum of seventeen and ten
pls help
Answer: so you would do 17 plus ten which is 27 so triple 3 so your answer is 27^3
Step-by-step explanation:
sum so your adding plus you need the exponent which is times 3
The Sears Tower, at 1,451 feet, is one of the tallest structures in the United States. A penny is thrown from the top of the tower. The height, h, of the penny is recorded after each second, t, in the table. Write an equation for the curve of best fit, then find the approximate height of the penny after 7 seconds.
Answer:
The equation for the height of the penny in function of time is:
[tex]h(t)=1451-16t^2[/tex]
After 7 seconds, the penny will be at a height of 667 feet.
Step-by-step explanation:
The penny will have a free fall.
The initial velocity is zero, and the initial height is h(0)=1,451.
The acceleration will be the gravity, that has a value g=32 ft/s^2.
Then, we can model this starting by the speed:
[tex]dv/dt=-g\\\\v(t)=v_0-gt=-gt[/tex]
Then, the height becomes:
[tex]dh/dt=v(t)=-gt\\\\h(t)=h_0-\dfrac{gt^2}{2}=1451-\dfrac{32}{2}t^2\\\\\\h(t)=1451-16t^2[/tex]
The approximate height of the penny after 7 seconds can be calculated as:
[tex]h(7)=1451-16(7^2)=1451-16*49=1451-784=667[/tex]
After 7 seconds, the penny will be at a height of 667 feet.
Find the surface area of the pyramid to the nearest whole number.
Answer:
i think its 248m^2
Step-by-step explanation:
Subtracting by adding up 65-39
Answer:
26Step-by-step explanation:
In order to subtract by adding up 65-39, we need to add -39 to the value of 65. This can be rewritten in this way;
65+(-39)
The equation above is similar to the one given because the product of a minus and a plus sign will still give us back a minus sign.
on solving;
65+(-39) = 26
If you roll a die three times, what is the probability of rolling three ONES?
(Give your answer as a decimal, rounded to the nearest thousandth. That is, rounded to three decimal places.)
Answer:
0.004
Step-by-step explanation:
The probability of rolling any number is 1/6 so that times 3 is 1/216 that as a decimal i 0.004
A grocery store has an average sales of $8000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 days of sales was selected. It was found that the average was $8300 per day. From past information, it is known that the standard deviation of the population is $1200. The p-value is
Answer:
The p-value of the test is 0.023.
Step-by-step explanation:
In this case we need to determine whether the addition of several advertising campaigns increased the sales or not.
The hypothesis can be defined as follows:
H₀: The stores average sales is $8000 per day, i.e. μ = 8000.
Hₐ: The stores average sales is more than $8000 per day, i.e. μ > 8000.
The information provided is:
[tex]n=64\\\bar x=\$8300\\\sigma=\$1200[/tex]
As the population standard deviation is provided, we will use a z-test for single mean.
Compute the test statistic value as follows:
[tex]z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}=\frac{8300-8000}{1200/\sqrt{64}}=2[/tex]
The test statistic value is 2.
Decision rule:
If the p-value of the test is less than the significance level then the null hypothesis will be rejected.
Compute the p-value for the two-tailed test as follows:
[tex]p-value=P(Z>2)\\=1-P(Z<2)\\=1-0.97725\\=0.02275\\\approx 0.023[/tex]
*Use a z-table for the probability.
The p-value of the test is 0.023.
Three methods, A, B and C, are available for teaching a certain industrial skill. The failure rate is 15% for A, 5% for B and 10% for C. The method A is used 30%, B is used 40% and C is used 30% of the time. A worker is taught the skill by one of the methods but fails to learn it correctly. a. (10 points) What is the probability that he was taught by method A? b. (5 points) What is the probability of B given A?
Answer:
a) so the correct answer is that the probability that method A has been taught is 0.4737
b) the probability that B receives A is 0.5
Step-by-step explanation:
With the previous data we know that 3 methods teach an industrial skill and when putting into practice a worker does not learn, we have the failure rates like this:
method A fails 15%
method B fails: 5%
method C fails: 10%
usage percentages:
A: 30%
B: 40%
C: 30%
a) the probability that method A has been taught is as follows:
P (failure rate) = P (A) * P (failure rate A) + P (B) * P (failure rate B) + P (C) * P (failure rate C)
we replace the data obtaining:
P = 0.3 * 0.15 + 0.4 * 0.05 + 0.3 * 0.1 = 0.095
P ( failure rate A) = P (A) * P (failure rate A) / P (failure rate)
we replace the data obtaining:
0.3 * 0.15 / 0.095 = 0.4737
so the correct answer is that the probability that method A has been taught is 0.4737
b) the probability that B receives A is as follows:
P (B | A) = P (B) = 0.50
Find the greatest common factor of the
following monomials:
34c3 2c5
Answer:2c^2
Step-by-step explanation:
34c^3 and 2c^5
34c^3=2 x 16 x c x c^2
2c^5=2 x c^2 x c^3
Greatest common factor =2 x c^2
Greatest common factor =2c^2
