Answer:
16x+36
Step-by-step explanation:
4(4x + 9)
16x+36
____________________________________
Solution,
4(4x+9)
=4*4x+4*9
=16x+36
So the answer is 16x+36
Hope it helps
Good luck on your assignment
___________________________________
Help me solve (b) in this quadrilateral
Answer:
b = 87°
Step-by-step explanation:
In order to answer this question, we need to utilise an important angle fact which is angles in a quadrilateral add up to 360°
Using the information we can set up an equation to find the value of b
→ Form equation
63 + 140 + 70 + b = 360
→ Simplify
273 + b = 360
→ Minus 273 from both sides isolate b
b = 87°
Answer:
Hello!
The answer is 87 degrees!
I hope I was of help! If not please let me know! Thank you!
Step-by-step explanation:
Solve x for the diagram below.
Answer:
20°
Step-by-step explanation:
These angles add up to 90° so we have:
x + 2x + x + 10 = 90
4x + 10 = 90
4x = 80
x = 20°
Please answer this correctly
Answer:
A = 1/2 b*h
A = 24
b = 8
h = ?
24 = 1/2 * 8 * h
24 = 4h
h = 6
The height is 6 cm.
Hope this helps.
Please everyone help me!
Answer:g=0 is not the solution
Step-byd-step explanation:
-1 1/2 is a negative number and 0 is not negative
Answer:
g=0
Step-by-step explanation:
happy to help ya :)
which of the following expressions is equal to -3x^2-12??!!! please help him
Answer:
-3 ( x+2i) (x-2i)
Step-by-step explanation:
-3x^2-12
Factor out a -3
-3(x^2 +4)
Rewrite
-3 ( x^2 - -4)
-3 ( x^2 - (-2i)^2) This is the difference of squares ( a^2 -b^2 ) = (a-b)(a+b)
-3 ( x- -2i) (x+2i)
-3( x+2i) (x-2i)
An amount was invested at r% per quarter. What value of r will ensure that accumulated amount at the end of one year is 1.5 times more than amount invested? Correct to 2 decimal places
Answer:
25.75 % interest rate
Step-by-step explanation:
Given:
Amount was invested = r% per quarter
Amount invested = P
Rate of interest = r % per quarter
Time (n) = 4 Quarters
Computation:
A = P(1 + r/100)ⁿ
According to question.
⇒ A = P + 1.5P = 2.5P
⇒ 2.5P = P(1 + r/100)⁴
⇒ 2.5 = (1 + r/100)⁴
⇒ 1 + r/100 = 1.2575
⇒ r/100 = 0.2575
⇒ r = 25.75
25.75 % interest rate
You have 125 g of a certain seasoning and are told that it contains 14.0 g of salt. What is the percentage of salt by mass in this seasoning? Express the percentage numerically. Do not round.
Answer:
[tex]\frac{14}{125}\times 100=11.2\%[/tex]
Find the VOLUME of this composite solid.
Answer:
(294π +448) cm³ ≈ 1371.6 cm³
Step-by-step explanation:
The half-cylinder at the right end has a radius of 7 cm, as does the one on top. Together, the total length of these half-cylinders is 8 cm + 4cm = 12 cm. That is equivalent in volume to a whole cylinder of radius 7 cm that is 6 cm long.
The cylinder volume is ...
V = πr²h = π(7 cm)²(6 cm) = 294π cm³
__
The cuboid underlying the top half-cylinder has dimensions 4 cm by 8 cm by 14 cm (twice the radius). So, its volume is ...
V = LWH = (4 cm)(8 cm)(14 cm) = 448 cm³
Then the total volume of the composite figure is ...
(294π +448) cm³ ≈ 1371.6 cm³
Find the m∠YAX in the figure below
Answer:
76
Step-by-step explanation:
The two angles are vertical angles so they are equal
3x+7 = 4x-16
Subtract 3x from each side
3x-3x+7 = 4x-3x-16
7 = x-16
Add 16 to each side
7+16 = x-16+16
23 =x
We want YAX
YAX = 3x+7
3*23+7
69+7
76
A Biology test contains 10 multiple choice questions each with 5 choices and one correct answer. If a law school student just randomly guesses on each of the 10 questions, i.e., the probability of getting a correct answer on any given question is 0.2. Assume that all questions are answered independently. (a) What is the probability that the student answers at least 9 questions correctly
Answer:
0.0004% probability that the student answers at least 9 questions correctly
Step-by-step explanation:
For each question, there are only two possible outcomes. Either the student guesses the correct answer, or he does not. All questions are answered independently. This means that we use the binomial distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
In this question, we have that:
[tex]n = 10, p = 0.2[/tex]
What is the probability that the student answers at least 9 questions correctly
[tex]P(X \geq 9) = P(X = 9) + P(X = 10)[/tex]
In which
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 9) = C_{10,9}.(0.2)^{9}.(0.8)^{1} = 0.000004[/tex]
[tex]P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} \approx 0 [/tex]
[tex]P(X \geq 9) = P(X = 9) + P(X = 10) = 0.000004 + 0 = 0.000004[/tex]
0.0004% probability that the student answers at least 9 questions correctly
Maddie is packing moving boxes. She has one 3 cubic-foot box and one 6 cubic-foot box. How many cubic feet of clothing can she fit in the two boxes?
8 9 10 12
Answer:
She can fit 9 cubic feet of clothing in the two boxes.
Step-by-step explanation:
She can fit a total of 3 cubic feet of clothing in one box, and the other she can fit a total 6 cubic feet.
3 + 6 = 9
Answer:
9 cu ft.
Step-by-step explanation:
That is the sum of the capacities of the 2 boxes
= 3 + 6
= 9 cu ft.
What is the product of (n -8)(n + 2)?
n2 - 10n - 16
n2 + 10n - 16
n2 - On - 16
in 2 + 6n - 16
Answer:
n2-6n-16
Step-by-step explanation:
n(n+2)-8(n+2)
n2+2n-8n-16=
n2-6n-16
Answer: n 2 + 6n - 16
Step-by-step explanation:
Show all work to solve the equation for x. If a solution is extraneous, be sure to identify it. Square root of the quantity x + 6 end quantity - 4 = x.
Answer:
x = 2 is the solution of the given equation
Step-by-step explanation:
Step(i):-
Given equation
[tex]\sqrt{x+6-4} = x[/tex]
squaring on both sides , we get
[tex](\sqrt{x+2})^{2} = x^{2}[/tex]
⇒ x + 2 = x²
⇒x² - x -2 =0
Step(ii):-
Given x² - x -2 =0
⇒ x² - 2x + x - 2 =0
⇒ x ( x-2) + 1(x - 2) =0
⇒ (x + 1) ( x-2) =0
⇒ x = -1 and x =2
x = 2 is the solution of the given equation
Verification:-
[tex]\sqrt{x+6-4} = x[/tex]
Put x= 2
[tex]\sqrt{2+6-4} = 2[/tex]
[tex]\sqrt{4} = 2[/tex]
2 = 2
Please help me with this problem I'm lost
Answer:
24
Step-by-step explanation:
Multiple (4)(2)= 8
-3(8) =24
Submit A political scientist wants to conduct a research study on a president's approval rating. The researcher has obtained data that states that 45% of citizens are in favor of the president. The researcher wants to determine the probability that 6 out of the next 8 individuals in his community are in favor of the president. What is the binomial coefficient of this study? Write the answer as a number, like this: 42.
Answer: 28
Step-by-step explanation: Im taking the same class here is a photo of the work, divide 56/2 than you get 28
Please answer this correctly
Answer:
d = 2
the diagonals are the different lengths
Step-by-step explanation:
Consider the following dice game, as played at a certain gambling casino: players 1 and 2 roll a pair of dice in turn. the bank then rolls the dice to determine the outcome according to the following rule: player i,i=1,2, wins if his roll is strictly
Ii={1 if i wins, 0 otherwise}
and show that I1 and I2 are positively correlated. Explain why this result was to be expected.
Answer:
they are positively correlated.
Step-by-step explanation:
We can calculate the individal expectations first. FIrst player will win if that player's roll is greater than the bank's roll. There are (6 possible rolls of player 1 * 6 possible rolls of bank =) 36 total possible rolls, out of which player 1 will win in 15 cases.
[tex]\therefore E(I_i) = 1\cdot \frac{15}{36} + 0 \cdot \frac{21}{36} = \frac{5}{12} \approx 0.4167[/tex]
For the joint expectation, there are (6 possible rolls of player 1 * 6 possible rolls of player 2 * 6 possible rolls of bank =) 216 total possible rolls.
Cases where both players win: Expectation = $2.
If bank rolls 1, both players will win in 5*5 = 25 cases. P1 is one of {2,3,4,5,6}, P2 is one of {2,3,4,5,6}
If bank rolls 2, both players will win in 4*4 = 16 cases.
If bank rolls 3, both players will win in 3*3 = 9 cases.
If bank rolls 4, both players will win in 2*2 = 4 cases.
If bank rolls 5, both players will win in 1*1 = 1 cases.
If bank rolls 6, both players will win in 0*0 = 0 cases.
Total cases = 25+16+9+4+1+0 = 55 cases.
Cases where player 1 wins $1 and player 2 loses: Expectation = $1.
If bank rolls 1, player 1 will win and player 2 will lose in 5*1 = 5 cases. P1 is one of {2,3,4,5,6}, P2 is {1}
If bank rolls 2, player 1 will win and player 2 will lose in 4*2 = 8 cases.
If bank rolls 3, player 1 will win and player 2 will lose in 3*3 = 9 cases.
If bank rolls 4, player 1 will win and player 2 will lose in 2*4 = 8 cases.
If bank rolls 5, player 1 will win and player 2 will lose in 1*5 = 5 cases.
If bank rolls 6, player 1 will win and player 2 will lose in 0*6 = 0 cases.
Total cases = 5+8+9+8+5+0 = 35
Cases where player 2 wins $1 and player 1 loses: Expectation = $1.
This is the same as above with player 1 and 2 exchanged.
Total cases = 35
Cases where both players lose: Expectation = $0.
If bank rolls 1, both players will lose in 1*1 = 1 cases. P1 is {1}, P2 is {1}
If bank rolls 2, both players will lose in 2*2 = 4 cases.
If bank rolls 3, both players will lose in 3*3 = 9 cases.
If bank rolls 4, both players will lose in 4*4 = 16 cases.
If bank rolls 5, both players will lose in 5*5 = 25 cases.
If bank rolls 6, both players will lose in 6*6 = 36 cases.
Total cases = 1+4+9+16+25+36 = 91 cases.
Total of all cases (we expect this to be 216 as mentioned above) = 55+35+35+91=216
So, joint expectation is:
[tex]E(I_1I_2) = \frac{2\cdot 55 +1\cdot 35+1\cdot 35+0\cdot 91}{216} = \frac{180}{216}= \frac{5}{6} \approx 0.8333[/tex]
So, the covariance is given by:
[tex]\texttt{Cov}(I_1I_2) =E(I_1I_2) -E(I_1)\cdot E(I_2)= \frac{5}{6}-\frac{5}{12}\cdot\frac{5}{12}=\frac{95}{144} \approx 0.6597[/tex]
As this is greater than 0 and closer to 1, they are positively correlated.
The reason why this result is expected is because the same bank roll is being used for both players. So, it is very likely that both players will win if the bank roll is 1 or even 2. Also, it is very likely that both players will lose if the bank roll is 6, 5, or even 4. This shows positive correlation between the events.
A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1521 and the standard deviation was 314. The test scores of four students selected at random are 1920, 1290, 2220, and 1420. Find the z-scores that correspond to each value and determine whether any of the values are unusual
Answer:
A score of 1920 has a z-score of 1.27.
A score of 1290 has a z-score of -0.74.
A score of 2220 has a z-score of 2.23.
A score of 1420 has a z-score of -0.32.
The score of 2220 is more than two standard deviations from the mean, so it is unusual.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
If X is 2 or more standard deviations from the mean, it is considered unusual.
In this question, we have that:
[tex]\mu = 1521, \sigma = 314[/tex]
Score of 1920:
X = 1920. Then
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{1920 - 1521}{314}[/tex]
[tex]Z = 1.27[/tex]
A score of 1920 has a z-score of 1.27.
Score of 1290:
X = 1290. Then
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{1290 - 1521}{314}[/tex]
[tex]Z = -0.74[/tex]
A score of 1290 has a z-score of -0.74.
Score of 2220:
X = 1290. Then
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{2220 - 1521}{314}[/tex]
[tex]Z = 2.23[/tex]
A score of 2220 has a z-score of 2.23.
Since it is more than 2 standard deviations of the mean, the score of 2220 is unusual.
Score of 1420:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{1420 - 1521}{314}[/tex]
[tex]Z = -0.32[/tex]
A score of 1420 has a z-score of -0.32.
Determine the maximum r-value of the polar equation r = 3 + 3 cos theta
Answer:
Step-by-step explanation:
6
Please help! Correct answer only, please! The following information matrices shows how many of each vehicle type sold and the bonus amount each salesperson receives for selling that type of vehicle for the car dealership for the week. What does the element LaTeX: A_{2,3}A 2 , 3represent? A. Mark sold 2 vans B. Scott sold 1 Van C. Mark sold 4 trucks D. Kelly sold 2 trucks
Answer: B) Scott sold 1 van
Step-by-step explanation:
A₂,₃ represents: matrix A - 2nd row - 3rd column
The second row is Scott and and the 3rd row is Vans
If you look at Scott - Vans, you will see that Scott sold 1 van.
You play a game that requires rolling a six sided die then randomly choosing a card from a deck containg 8 red cards ,6 blue cards and 8 yellow cards whats the probability that younroll a 3 on the due and choose a red card
Answer:
2/33
Step-by-step explanation:
Probability that a 3 is rolled on the die = 1/6 (equal chance of rolling any number)
Probability of choosing a red card = 8/22 (8 red cards, 22 cards in total)
8/22 = 4/11
Probability of rolling a 3 AND choosing a red card = 1/6 x 4/11
= 4/66
= 2/33
Jack buys a bag of 5 apples, each
equal in size. He eats of 1/2 of one apple.
What fraction of the bag of
apples did he eat?
Answer:
4 1/2
Step-by-step explanation:
5 apples - 1/2 apple =
4 1/2 apple
or
9/2
* If you are given the measurements of two sides of a triangle,
what will be true about the triangles you make?
Answer:both sides will be equal
Step-by-step explanation:
adiocarbon dating of blackened grains from the site of ancient Jericho provides a date of 1315 BC ± 13 years for the fall of the city. What is the relative amount of 14C in the old grain vs the new grain in 2007 AD? (A0 = original radioactivity; At = radioactivity in 2007 AD).
Answer:
[tex]\left(\frac{m(t)}{m_{o}} \right)_{min} \approx 0.659[/tex] and [tex]\left(\frac{m(t)}{m_{o}} \right)_{max} \approx 0.661[/tex]
Step-by-step explanation:
The equation of the isotope decay is:
[tex]\frac{m(t)}{m_{o}} = e^{-\frac{t}{\tau} }[/tex]
14-Carbon has a half-life of 5568 years, the time constant of the isotope is:
[tex]\tau = \frac{5568\,years}{\ln 2}[/tex]
[tex]\tau \approx 8032.926\,years[/tex]
The decay time is:
[tex]t = 1315\,years + 2007\,years \pm 13\,years[/tex] (There is no a year 0 in chronology).
[tex]t = 3335 \pm 13\,years[/tex]
Lastly, the relative amount is estimated by direct substitution:
[tex]\frac{m(t)}{m_{o}} = e^{-\frac{3335\,years}{8032.926\,years} }\cdot e^{\mp\frac{13\,years}{8032.926\,years} }[/tex]
[tex]\left(\frac{m(t)}{m_{o}} \right)_{min} = e^{-\frac{3335\,years}{8032.926\,years} }\cdot e^{-\frac{13\,years}{8032.926\,years} }[/tex]
[tex]\left(\frac{m(t)}{m_{o}} \right)_{min} \approx 0.659[/tex]
[tex]\left(\frac{m(t)}{m_{o}} \right)_{max} = e^{-\frac{3335\,years}{8032.926\,years} }\cdot e^{\frac{13\,years}{8032.926\,years} }[/tex]
[tex]\left(\frac{m(t)}{m_{o}} \right)_{max} \approx 0.661[/tex]
A recent survey found that 86% of employees plan to devote at least some work time to follow games during the NCAA Men's Basketball Tournament. A random sample of 100 employees was selected. What is the probability that less than 80% of this sample will devote work time to follow games?
Answer:
4.18% probability that less than 80% of this sample will devote work time to follow games
Step-by-step explanation:
Normal probability distribution
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
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]
In this question, we have that:
[tex]p = 0.86, n = 100[/tex]
So
[tex]\mu = 0.86, s = \sqrt{\frac{0.86*0.14}{100}} = 0.0347[/tex]
What is the probability that less than 80% of this sample will devote work time to follow games?
This is the pvalue of Z when X = 0.8. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.8 - 0.86}{0.0347}[/tex]
[tex]Z = -1.73[/tex]
[tex]Z = -1.73[/tex] has a pvalue of 0.0418
4.18% probability that less than 80% of this sample will devote work time to follow games
Find the length of Line segment A C . Use that length to find the length of Line segment C D . Triangle A B C is shown. A perpendicular bisector is drawn from point A to point C on side B D. Angle A B C is 30 degrees and angle A D C is 25 degrees. The length of A B is 10 centimeters. What is the length of Line segment C D? Round to the nearest tenth. 2.3 cm 4.0 cm 10.7 cm 18.6 cm
Answer:
10.7 CM
Step-by-step explanation:
Correct on Edge 2020
Answer:
answer is C 10.7 cm
Step-by-step explanation:
got it right on edg 2020-2021
8. Mr. Azu invested an amount at rate of 12% per annum and invested another amount, GH¢
580.00 more than the first at 14%. If Mr. Azu had total accumulated amount of
GH¢2,358.60, how much was his total investment?
Answer:
GH¢. 18098.46
Step-by-step explanation:
Let the first investment giving 12% interest per annum be Bank A
Let the 2nd investment giving 10% per annum be bank B
Let the first amount invested be
GH¢. X and let the second amount invested be GH¢. X + 580
Thus; In bank A;
Principal amount in first = GH¢. x
rate = 12 %
time = 1 year
Formula for simple interest = PRT/100
Where P is principal, R is rate and T is time.
So, interest in his investment = 12X/100 = 0.12X
while in bank B;
principal amount = GH¢. X + 580
rate = 14%
time = 1 yr
So, interest in his investment = [(X + 580) × 14]/100
= 0.14(X + 580)
So, total accumulated interest is;
0.12X + 0.14(X + 580) = 0.12X + 0.14X + 81.2 = 0.26X + 81.2
Now, we are given accumulated interest = GH¢. 2,358.60
Thus;
2358.60 = (0.26X + 81.2)
2358.6 - 81.2 = 0.26X
X = 2277.4/0.26
X = 8759.23
So,
first amount invested = GH¢. 8759.23
Second amount invested = GH¢. 8759.23 + GH¢. 580 = GH¢. 9339.23
Total amount invested = GH¢. 8759.23 + GH¢. 9339.23 = GH¢. 18098.46
A man is giving a dinner party. His current wine supply includes 8 bottles of zinfandel, 10 of merlot, and 12 of cabernet, all from different wineries. a) If he wants to serve 3 bottles of zinfandel and serving order is important, how many ways are there to do this? (2 points) b) If 6 bottles are randomly selected, what is the probability that this results in two bottles of each variety being chosen? (4 points) c) If 6 bottles are randomly selected, what is the probability that all of them are the same variety?
Answer:
a. 336
b. 14.01%
c. 0.2%
Step-by-step explanation:
a. We have that the number of zinfandel bottles is 8 and that the number of zinfandel served is 3, therefore:
n = 8 and r = 3
we can calculate it by means of permutation:
nPr = n! / (n-r)!
replacing:
8P3 = 8! / (8-3)!
8P3 = 336
Which means there are 336 ways.
b. First we must calculate the ways to choose 2 bottles of each variety, through combinations:
nCr = n! / (r! * (n-r)!
We know that there are 8 bottles zinfandel, 10 of merlot, and 12 of cabernet, and we must choose 2 of each, therefore it would be:
8C2 * 10C2 * 12C2
8! / (2! * (8-2)! * 10! / (2! * (10-2)! * 12! / (2! * (12-2)!
28 * 45 * 66 = 83160
Now we must calculate the total number of ways, that is, choose 6 bottles of the 30 total (8 + 10 + 12)
30C6 = 30! / (6! * (30-6)! = 593775
Thus:
83160/593775 = 0.1401
In other words, the probability is 14.01%
c. In this case, we must calculate the number of ways of 8 bottles zinfandel, 10 of merlot, and 12 of cabernet choose 6, that is to say that they are all of the same variety, therefore:
8C6 + 10C6 + 12C6
8! / (6! * (8-6)! + 10! / (6! * (10-6)! + 12! / (6! * (12-6)!
28 + 210 + 924 = 1162
And that divide it by the total amount that we calculated the previous point, 30C6 = 593775
Thus:
1162/593775 = 0.002
In other words, the probability 0.2%
Susan designed a circular pool with diameter of 25 meters. What is the area of the bottom of the pool?
Answer: Area = 490.87 meters
Step-by-step explanation:
A=πr2
r = 12.5 (1/2 of diameter)
A = 490.87 meters
Step-by-step explanation:
We know that the formula to find the area of a circle is πr^2 or in other words, pi times the radius squared. We have been given the diamter of 25 inches. We know that the diamater is double the radius. 25 divided by 2 will get us 12.5. If we write this in equation form (or substitute the variables) will be written as: (3.14)12.5^2, 3.14 being pi. Now, we would multiply the radius by radius (because it's squared) or in other words, (12.5*12.5) to equal 156.25. If we write this in equation form, we would get: 3.14(156.25). Now we finally multiply pi (3.14) times 156.25 to equal 490.625 or rounded to the tenth 490.6
Barron's reported that the average number of weeks an individual is unemployed is 18.5 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 18.5 weeks and that the population standard deviation is 6 weeks. Suppose you would like to select a sample of 55 unemployed individuals for a follow-up study.
A) show the sampling distribution of x, the sample mean average for a sample of 50 unemployment individuals.B) What is the probability that a simple random sample of 50 unemployment individuals will provide a sample mean within one week of the population mean?C) What is the probability that a simple random sample of 50 unemployed individuals will provide a sample mean within a half week of the population mean?
Answer:
A) The sampling distribution for a sample size n=50 has a mean of 18.5 weeks and a standard deviation of 0.849.
B) P = 0.7616
C) P = 0.4441
Step-by-step explanation:
We assume that for the population of all unemployed individuals the population mean length of unemployment is 18.5 weeks and that the population standard deviation is 6 weeks.
A) We take a sample of size n=50.
The mean of the sampling distribution is equal to the population mean:
[tex]\mu_s=\mu=18.5[/tex]
The standard deviation of the sampling distribution is:
[tex]\sigma_s=\dfrac{\sigma}{\sqrt{n}}=\dfrac{6}{\sqrt{50}}=0.849[/tex]
B) We have to calculate the probability that the sampling distribution gives a value between one week from the mean. That is between 17.5 and 19.5 weeks.
We can calculate this with the z-scores:
[tex]z_1=\dfrac{X_1-\mu}{\sigma/\sqrt{n}}=\dfrac{17.5-18.5}{6/\sqrt{50}}=\dfrac{-1}{0.8485}=-1.179\\\\\\z_2=\dfrac{X_2-\mu}{\sigma/\sqrt{n}}=\dfrac{19.5-18.5}{6/\sqrt{50}}=\dfrac{1}{0.8485}=1.179[/tex]
The probability it then:
[tex]P(|X_s-\mu_s|<1)=P(|z|<1.179)=0.7616[/tex]
C) For half a week (between 18 and 19 weeks), we recalculate the z-scores and the probabilities:
[tex]z=\dfrac{X-\mu}{\sigma/\sqrt{n}}=\dfrac{18-18.5}{6/\sqrt{50}}=\dfrac{-0.5}{0.8485}=-0.589[/tex]
[tex]P(|X_s-\mu_s|<0.5)=P(|z|<0.589)=0.4441[/tex]
