Answer:
0.0264 = 2.64% probability that the proportion of wrong numbers in a sample of 448 phone calls would differ from the population proportion by more than 3%
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
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]
A telephone exchange operator assumes that 9% of the phone calls are wrong numbers.
This means that [tex]p = 0.09[/tex]
Sample of 448
This means that [tex]n = 448[/tex]
Mean and standard deviation:
[tex]\mu = p = 0.09[/tex]
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.09*0.91}{448}} = 0.0135[/tex]
What is the probability that the proportion of wrong numbers in a sample of 448 phone calls would differ from the population proportion by more than 3%?
More than 9% + 3% = 12 or less than 9% - 3% = 6%. Since the normal distribution is symmetric, these probabilities are the same, so we find one of them and multiply by 2.
Probability it is less than 6%
P-value of Z when X = 0.06. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.06 - 0.09}{0.0135}[/tex]
[tex]Z = -2.22[/tex]
[tex]Z = -2.22[/tex] has a p-value of 0.0132
2*0.0132 = 0.0264
0.0264 = 2.64% probability that the proportion of wrong numbers in a sample of 448 phone calls would differ from the population proportion by more than 3%
Write a compound inequality to represent all of the numbers between -4 and 6.
Answer:
-4 < x < 6
Step-by-step explanation:
Which would result in a lower price to first discount an item by 10% and then by a further 15%, OR to first discount an item by 15% and then by a further 10%. Justify your reasoning.
Answer:
Neither one. They will both result in the same price.
Step-by-step explanation:
To discount an item 10%, you charge 90% of the price of the item. To find 90% of a price, you multiply the price by 0.9.
To discount an item 15%, you charge 85% of the price of the item. To find 85% of a price, you multiply the price by 0.85.
Since multiplication is commutative, multiplying a number by 0.9 and then by 0.85 is the same as multiplying the number by 0.85 first and then by 0.9.
Let's say the item costs x.
Take off the 10% discount first: 0.9x
Now take off the 15% discount: 0.85 * (0.9x)
Now do it the other way.
Take off the 15% discount first: 0.85x
Now take off the 10% discount: 0.9 * (0.85x)
Since 0.85 * 0.9 * x = 0.9 * 0.85 * x, the results are the same.
Answer: neither
Suppose z varies directly with x and inversely with the square of y. If z = 16 when x = 4 and y = 1 , what is z when x = 8 and y = 9 ?
Answer:
z = 3.6
Step-by-step explanation:
Given that,
z varies directly with x and inversely with the square of y. We can write it as :
[tex]z\propto \dfrac{x}{y}\\\\z=\dfrac{kx}{y}[/tex]
Where
k is constant
Put z = 16 when x = 4 and y = 1
[tex]16=\dfrac{k\times 4}{1}\\\\k=4[/tex]
Now put k = 4, x = 8 and y = 9
[tex]z=\dfrac{4\times 8}{9}\\\\z=3.6[/tex]
So, the value of z is equal to 3.6.
At that rate, about how many gallons of milk will they need to purchase in a year’s time?
Give your answer as a whole number.
Answer: 260 gallons
Step-by-step explanation:
We can use a proportion to solve this problem. We know that a family used 15 gallons of milk every 3 weeks. Since the problem asks for how much they will need for a year, we can gather that a year is 52 weeks. We can come up with the following proportion.
[tex]\frac{15}{3} =\frac{x}{52}[/tex] [cross multiply]
[tex]3x=780[/tex] [divide both sides by 3]
[tex]x=260[/tex]
Therefore, they will need to purchare 260 gallons.
What is 12 x 12 ?
A. 12
b. 144
c. 147
d. 2574
Answer:
b
Step-by-step explanation:
An RLC series circuit has an applied voltage of 240 volts. R = 48 ohm, XL = 100 ohm, and XC = 36 ohm. What is the circuit impedance (Z)?
9514 1404 393
Answer:
48 +j64 ohms
Step-by-step explanation:
The impedance of a series circuit is the sum ...
R + jXl -jXc
= 48 +j100 -j36
= 48 +j64 . . . . ohms
_____
Additional comment
"j" is the electrical engineer's name for √-1, because "i" is used to represent current.
Draw a line representing the "rise" and a line representing the "run" of the line. State the slope of the line in simplest form.
Answer:
See attachment showing the rise and run
Slope = 1
Step-by-step explanation:
In the diagram attached below, the rise is represented by the blue line, while the run is represented by the red line.
Rise = 4 units
Run = 4 units
It's a positive slope because the line slopes upwards from left to right
Slope = rise/run = 4/4
Slope = 1
Find the factors of function f, and use them to complete this statement. f(x)=2x^(4)-x^(3)-18x^(2)+9x
From left to right, function f has zeros at
Hello,
[tex]f(x)=2x^4-x^3-18x+9x\\\\=x(2x^3-x^2-18x+9)\\\\=x(x^2(2x-1)-9(2x-1))\\\\=x(2x-1)(x^2-9)\\=x(2x-1)(x-3)(x+3)\\[/tex]
Zeros are : 0; 1/2; -3; 3.
The zeros of the function are -3, 0, 1/2 and 3.
The given function is [tex]f(x)=2x^{4} -x^{3} -18x^{2} +9x[/tex].
What are the zeros of a function?Zeros of a function are the points where the graph of the function meets the X-axis i.e., at the solutions of f(x) = 0.
Now, factorise the given function, that is f(x)=x(2x³-x²-18x+9).
=x[x²(2x-1)-9x(2x-1)]
=x(2x-1)(x²-9)
=x(2x-1)(x+3)(x-3)
= -3, 0, 1/2, 3
Therefore, the zeros of the function are -3, 0, 1/2 and 3.
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Help please somebody ASAP
Answer:
[tex]\frac{-2x+11}{(x-4)(x+1)}[/tex]
Step-by-step explanation:
I don't think we can factor this so we'll have to multiply to make the denominators the same
[tex]\frac{3(x+1)}{(x^2-3x-4)(x+1)}-\frac{2(x^2-3x-4)}{(x+1)(x^2-3x-4)}\\\\\frac{3x+3-(2x^2-6x-8)}{(x^2-3x-4)(x+1)}=\frac{-2x^2+9x+11}{(x^2-3x-4)(x+1)}\\-2x^2+9x+11=(x+1)(-2x+11)\\\\x^2-3x-4=(x+1)(x-4)\\\frac{(x+1)(-2x+11)}{(x+1)(x-4)(x+1)}=\frac{-2x+11}{(x-4)(x+1)}[/tex]
Select the correct answer.
What is the domain of y = tan x?
A. (-0,0)
B. (0,7)
c. all stan
D. all x 91
Need Plato help
Answer: d all
Step-by-step explanation: Because The domain of the function y = tan (x)) is all real numbers except the values where cos (x) is equal to 0, that is, the values π 2 + π n for all integers n. The range of the tangent function is all real numbers.
For the problem I tried dividing but my answers were not correct. How can I solve this problem then? Can someone help me out here please?
Answer:
8
Step-by-step explanation:
5 = 40
1 = x
Then we multiply by the rule of crisscrossing
5 x X = 40 x 1
5x = 40 then divide both by 5
X = 8
Claim: Fewer than 94% of adults have a cell phone. In a reputable poll of 1004 adults, 86% said that they have a cell phone. Find the value of the test statistic.
Answer: The value of test statistic = -10.67
Step-by-step explanation:
Test statistic for proportion:
[tex]z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}[/tex]
, where p= population proportion
n= sample size
[tex]\hat{p}[/tex] = sample proportion
AS per given,
p=0.94, n= 1004, [tex]\hat{p}=0.86[/tex]
[tex]z=\dfrac{0.86-0.94}{\sqrt{\dfrac{0.94(1-0.94)}{1004}}}\\\\=\dfrac{-0.08}{\sqrt{\dfrac{0.0564}{1004}}}\\\\=\dfrac{-0.08}{\sqrt{0.0000561752988048}}\\\\=\dfrac{-0.08}{0.00749501826581}\\\\=-10.673756509\approx-10.67[/tex]
i.e. the value of test statistic = -10.67
A salesman receives a salary of RM 2000 per month. He wis receive a commission of RM 800 for each car he sells. If he sells n cars in a particular month,
a. Find his monthly salary when n = 18.
b. Express his salary in terms of n.
Answer:
a) month salary = RM(18×800+2000)
= RM 16400
b) his salary = RM(800n+2000)
Hope it helps
Find, correct to the nearest degree, the three angles of the triangle with the given ven
A(1, 0, -1), B(4, -3,0), C(1, 2, 3)
o
CAB =
O
LABC =
O
LBCA =
9514 1404 393
Answer:
∠CAB = 86°
∠ABC = 43°
∠BCA = 51°
Step-by-step explanation:
This can be done a couple of different ways (as with most math problems). We can use the distance formula to find the side lengths, then the law of cosines to find the angles. Or, we could use the dot product. In the end, the math is about the same.
The lengths of the sides are given by the distance formula.
AB² = (4-1)² +(-3-0)² +(0-(-1)) = 16 +9 +1 = 26
BC² = (1-4)² +(2-(-3))³ +(3-0)² = 9 +25 +9 = 43
CA² = (1-1)² +(0-2)² +(-1-3)² = 4 +16 = 20
From the law of cosines, ...
∠A = arccos((AB² +CA² -BC²)/(2·AB·CA)) = arccos((26 +20 -43)/(2√(26·20)))
∠A = arccos(3/(4√130)) ≈ 86°
∠B = arccos((AB² +BC² -AC²)/(2·AB·BC)) = arccos((26 +43 -20)/(2√(26·43)))
∠B = arccos(49/(2√1118)) ≈ 43°
∠C = arccos((BC² +CA² -AB²)/(2·BC·CA)) = arccos((43 +20 -26)/(2√(43·20)))
∠C = arccos(37/(4√215)) ≈ 51°
The three angles are ...
∠CAB = 86°
∠ABC = 43°
∠BCA = 51°
_____
Additional comment
This sort of repetitive arithmetic is nicely done by a spreadsheet.
Help me or ill fail plz
Answer:
1,108 in²
Step-by-step explanation:
SA = (12×20) + (2×20×5 + 2×12×5) + (2×½×12×9)
+ (2×20×11)
= 240+320+108+440
= 1,108 in²
Fill in the blanks with the correct verbs given below.
(croak, is ,brush, writes plays, chirp, combines, mows, are look , keeps rises ,has,
reflects leaves, walks, is)
1. Marry ......... to office every morning .Walking is good exercise.
2. We........ our teeth after dinner. It ..........them clean.
3. Salim......... for school everyday at 7:00 a.m.
4. The sun ..........at 5:00 a.m. these days. The days are getting longer.
5. The tiger ......an endangered animal. There are only 1410 tigers left.
6. Vikram Seth......... poetry, fiction and travelogues.
7. Sania Mirza......... tennis. She plays both singles and doubles.
8. Frogs....... ...and birds...........
9. Please ..........for my red shirt. I cannot find it.
10. The gardener ........ the loan once a week.
11. The moon ........the light of the sun.
12. The times of India......... a national newspaper.
13. The UN headquarters...... in Geneva.
14. Maya ........... a pet dog .Its name is Lily.
15. This book....... projects and activities.
Answer:
Fill in the blanks with the correct verbs given below.
(croak, is ,brush, writes plays, chirp, combines, mows, are look , keeps rises ,has,
reflects leaves, walks, is)
1. Marry ...keeps rises...... to office every morning .Walking is good exercise.
2. We...brush..... our teeth after dinner. It .....makes.....them clean.
3. Salim....wakes..... for school everyday at 7:00 a.m.
4. The sun ...rises.......at 5:00 a.m. these days. The days are getting longer.
5. The tiger chirp......an endangered animal. There are only 1410 tigers left.
6. Vikram Seth.....combines........ poetry, fiction and travelogues.
7. Sania Mirza....plays..... tennis. She plays both singles and doubles.
8. Frogs....croak... ...and birds.....chirp......
9. Please ....look......for my red shirt. I cannot find it.
10. The gardener .....mows....... the loan once a week.
11. The moon ...keep rises.....the light of the sun.
12. The times of India......writes....... a national newspaper.
13. The UN headquarters.....is..... in Geneva.
14. Maya ...has........ a pet dog .Its name is Lily.
15. This book....writes..... projects and activities
01:55:07
The point-slope form of the equation of the line that passes through (-9, -2) and (1, 3) is y – 3 = {(x - 1). What is the
slope-intercept form of the equation for this line?
O y = 3x+2
O y= 2x-4
O y=+*+
O y = 3x - 2
Answer
y = 3x - 2
Step-by-step explanation
The slope-intercept form of the equation for this line is,
⇒ y = x + 2
What is Equation of line?The equation of line in point-slope form passing through the points
(x₁ , y₁) and (x₂, y₂) with slope m is defined as;
⇒ y - y₁ = m (x - x₁)
Where, m = (y₂ - y₁) / (x₂ - x₁)
Given that;
The point-slope form of the equation of the line that passes through points (-9, -2) and (1, 3) is,
⇒ y - 3 = (x - 1)
Now, We can simplify as;
⇒ y - 3 = (x - 1)
⇒ y - 3 + 3 = (x - 1) + 3
⇒ y = x + 2
Thus, The slope-intercept form of the equation for this line is,
⇒ y = x + 2
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haggle is making fruit basket which include apples and bananas to send to some of her estate clients she wants each basket to have at least 12 pieces of fruit, but the fruit should weigh no more than 80 ounces total. on average each apple weighs 5 ounces and each banana weighs 7 ounces. which system of inequalities can be used to determine the number of apples, x, and banana, y, that battle should include in each basket?
The requirement is fulfilled when 10 bananas and 2 apples are kept in the basket.
The equation can be given as
10y + 2x = 80
Here,
y means 7 ounces (weight of banasas)
x means 5 ounces (weight of apples)
Find the value for x
Answer:
[tex]180 - 2x + 180 - 4x + x = 180 \\ 360 - 5x = 180 \\ 180 = 5x \\ x = 36[/tex]
Simplify the ratio.
2.25 to 0.5
Answer:
9:2
Step-by-step explanation:
Given the following formula, solve for r.
The number of diners at a restaurant each day is recorded and a daily average is calculated every month (assume 30 days in a month). The number of diners each day has a mean of 107 and a standard deviation of 60, but does not necessarily follow a normal distribution.The probability that a daily average over a given month is greater than x is 2.5%. Calculate x. You may find standard normal table useful. Give your answer to 3 decimal places.x =
Answer:
x = 128.472
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
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.
The number of diners each day has a mean of 107 and a standard deviation of 60.
This means that [tex]\mu = 107, \sigma = 60[/tex]
Distribution of the daily average:
Over a month of 30 days, so [tex]n = 30, s = \frac{60}{\sqrt{30}} = 10.955[/tex]
The probability that a daily average over a given month is greater than x is 2.5%. Calculate x.
This is X when Z has a p-value of 1 - 0.025 = 0.975, so X when Z = 1.96. Then
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]1.96 = \frac{X - 107}{10.955}[/tex]
[tex]X - 107 = 1.96*10.955[/tex]
[tex]X = 128.472[/tex]
So x = 128.472
Please help NO LINKS
[tex]\bar{x} = 0[/tex]
[tex]\bar{y} =\dfrac{136}{125}[/tex]
Step-by-step explanation:
Let's define our functions [tex]f(x)\:\text{and}\:g(x)[/tex] as follows:
[tex]f(x) = x^2 + 1[/tex]
[tex]g(x) = 6x^2[/tex]
The two functions intersect when [tex]f(x)=g(x)[/tex] and that occurs at [tex]x = \pm\frac{1}{5}[/tex] so they're going to be the limits of integration. To solve for the coordinates of the centroid [tex]\bar{x}\:\text{and}\:\bar{y}[/tex], we need to solve for the area A first:
[tex]\displaystyle A = \int_a^b [f(x) - g(x)]dx[/tex]
[tex]\displaystyle \:\:\:\:\:\:\:=\int_{-\frac{1}{5}}^{+\frac{1}{5}}[(x^2 + 1) - 6x^2]dx[/tex]
[tex]\displaystyle \:\:\:\:\:\:\:=\int_{-\frac{1}{5}}^{+\frac{1}{5}}(1 - 5x^2)dx[/tex]
[tex]\displaystyle \:\:\:\:\:\:\:=\left(x - \frac{5}{3}x^3 \right)_{-\frac{1}{5}}^{+\frac{1}{5}}[/tex]
[tex]\:\:\:\:\:\:\:= \dfrac{28}{75}[/tex]
The x-coordinate of the centroid [tex]\bar{x}[/tex] is given by
[tex]\displaystyle \bar{x} = \dfrac{1}{A}\int_a^b x[f(x) - g(x)]dx[/tex]
[tex]\displaystyle \:\:\:\:\:\:\:= \frac{75}{28}\int_{-\frac{1}{5}}^{+\frac{1}{5}} (x - 5x^3)dx[/tex]
[tex]\:\:\:\:\:\:\:=\dfrac{75}{28}\left(\dfrac{1}{2}x^2 -\dfrac{5}{4}x^4 \right)_{-\frac{1}{5}}^{+\frac{1}{5}}[/tex]
[tex]\:\:\:\:\:\:\:= 0[/tex]
The y-coordinate of the centroid [tex]\bar{y}[/tex] is given by
[tex]\displaystyle \bar{y} = \frac{1}{A}\int_a^b \frac{1}{2}[f^2(x) - g^2(x)]dx[/tex]
[tex]\displaystyle \:\:\:\:\:\:\:=\frac{75}{28}\int_{-\frac{1}{5}}^{+\frac{1}{5}} \frac{1}{2}(-35x^4 + 2x^2 + 1)dx[/tex]
[tex]\:\:\:\:\:\:\:=\frac{75}{56} \left[-7x^5 + \frac{2}{3}x^3 + x \right]_{-\frac{1}{5}}^{+\frac{1}{5}}[/tex]
[tex]\:\:\:\:\:\:\:=\dfrac{136}{125}[/tex]
6. What are the coordinates of W? (0,t) W 0 (,0) Rhombus (0, -1) o (-r, o) (0,r). (t,0)
Answer:
B. (-r, 0)
Step-by-step explanation:
W is on the x axis, so the y coordinate is 0.
It is also r away from the origin, so the x coordinate is -r
Hope this helps!
Please help how to do this
Answer:
Frumpyton
Step-by-step explanation:
Since the standard deviation of Frumpyton is a lower number, this means a higher percentage of outcomes (job salaries) will be within a closer range to the mean salary. Since Frumpyton's standard deviation is $2,000 and the window your looking for is $32,000 to $36,000, if you go one interval up or down from the mean of $34,000, it falls in that range. Whereas, Dirtballville's standard deviation is $3,000 so it's more likely to fall outside of that range.
The population of a colony of 300 bacteria grows exponentially. After 2 hours, the population reaches 500. How much time will it take for the population to reach 9,600
Answer:
t = 13.56915448 hrs.
Step-by-step explanation:
500 = 300 [tex]e^{2k}[/tex]
5/3 = [tex]e^{2k}[/tex]
ln(5/3) = 2k ln(e)
k = ln(5/3)/2
k= 0.255412812
~~~~~~~~~~~~
9600 = 300 [tex]e^{0.255412812 t}[/tex]
32= [tex]e^{0.255412812 t}[/tex]
ln(32) = [tex]0.255412812 t[/tex] ln(e)
t = ln(32)/0.255412812
t = 13.56915448 hrs.
Round your number to the nearest hundredth 65 7
f(x) = 4x*x is a function?
Answer:
yes it is
Step-by-step explanation:
please i meed help!!! im stuck and cant concentrate
Answer:
A. 8h=m
Step-by-step explanation:
$8* h= total money m earned.
PLEASE HELP
The function in the table is quadratic:
TRUE
FALSE
Answer:
False
Step-by-step explanation:
Each f(x) increases by 8 therefore this equation is a linear function. If you where to graph it would be a straight line
Hope this helped :)
Answer:
False
Step-by-step explanation:
The slope is the same between all pounts which means the function is linear.
Hope this helps!