Answer:
a) 48.80% probability that his travel time to work is less than 30 minutes
b) The mean is 30.7 minutes and the standard deviation is of 3.83 minutes.
c) 13.13% probability that in a random sample of 36 NJ workers commuting to work, the mean travel time to work is above 35 minutes
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 normally distributed samples are solved using 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.
In this question, we have that:
[tex]\mu = 30.7, \sigma = 23[/tex]
a. If a worker is selected at random, what is the probability that his travel time to work is less than 30 minutes?
This is the pvlaue of Z when X = 30. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{30 - 30.7}{23}[/tex]
[tex]Z = -0.03[/tex]
[tex]Z = -0.03[/tex] has a pvalue of 0.4880.
48.80% probability that his travel time to work is less than 30 minutes
b. Specify the mean and the standard deviation of the sampling distribution of the sample means, for samples of size 36.
[tex]n = 36[/tex]
Applying the Central Limit Theorem, the mean is 30.7 minutes and the standard deviation is [tex]s = \frac{23}{\sqrt{36}} = 3.83[/tex]
c. What is the probability that in a random sample of 36 NJ workers commuting to work, the mean travel time to work is above 35 minutes?
This is 1 subtracted by the pvalue of Z when X = 35. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{35 - 30.7}{3.83}[/tex]
[tex]Z = 1.12[/tex]
[tex]Z = 1.12[/tex] has a pvalue of 0.8687
1 - 0.8687 = 0.1313
13.13% probability that in a random sample of 36 NJ workers commuting to work, the mean travel time to work is above 35 minutes
Two forces of magnitudes 16 and 20 pounds are acting on an object. The bearings of the forces are N75E and S20E (that is, 75∘ east of north and 20∘ east of south), respectively. How many degrees east of south is the resultant force? (Round to two decimal places and do not enter the ∘ symbol.)
Answer:
20.58
Step-by-step explanation:
Force A = 16 pounds
direction = N75E = 75° in the first quadrant
Force B = 20 pounds
direction = S20E = 180° - 20° = 160° in the fourth quadrants
we resolve the forces into their x and y resultant forces.
For the y axis forces,
-(16 x sin 75°) + (20 x sin 160°) = Fy
-15.45 + 6.84 = Fy
Fy = -8.61 N
For the x axis forces'
(16 x cos 75°) + (20 x cos 160°) = Fx
-4.14 - 18.79 = Fx
Fx = -22.93 N
Resultant force = [tex]\sqrt{(Fx)^{2} + (Fy)^{2} }[/tex] = [tex]\sqrt{(-8.61)^{2} + (-22.93)^{2} }[/tex]
Resultant force = 24.49 N
angle made by the resultant force is,
∅ = [tex]tan^{-1}[/tex] [tex]\frac{Fy}{Fx}}[/tex]
∅ = [tex]tan^{-1}[/tex] [tex]\frac{-8.61}{-22.93}}[/tex]
∅ = [tex]tan^{-1}[/tex] 0.3755
∅ = 20.58
In a sample of real estate ads, 62% of homes for sale have garages, 19% have swimming pools, and 15% have both features. What is the probability that a home for sale has a pool, a garage or both? State your answer as a decimal, not as a percent.
Answer:
66%
Step-by-step explanation:
15% of homes have both features.
The percentage of homes that have a pool and no garage is:
Pool only = 19% - 15% = 4%
The percentage of homes that have a garage and no pool is:
Garage only = 62% - 15% = 47%
Therefore, the percentage of homes that have a pool, a garage or both is:
[tex]P = 4\%+47\%+15\%\\P=66\%[/tex]
11. A square with sides
3/8
inch has a total area of:
Answer:
[tex](\frac{3}{8}\,in )^2=\frac{9}{64} \,in^2=0.140625\,\,i^2[/tex]
Step-by-step explanation:
Recall that the formula for the area of a square of side L is: [tex]Area=L^2[/tex]
Therefore, for this case:
[tex]Area=L^2\\Area = (\frac{3}{8} \,in)^2\\Area=\frac{9}{64} \,\,in^2\\Area=0.140625\,\,in^2[/tex]
A county real estate appraiser wants to develop a statistical model to predict the appraised value of houses in a section of the county called East Meadow. One of the many variables thought to be an important predictor of appraised value is the total number of rooms in the house. Consequently the appraiser decided to fit the simple linear regression model, ^y=β0+β1x , where y= the appraised value of the house (in thousands of dollars) and x= the number of rooms. Using data collected for a sample of n = 74 houses in East Meadow, the following results were obtained:
Answer:
Step-by-step explanation:
Hello!
The statistical model predicts the appraised value of houses in a section of the county East Meadow (Y) in relationship with the number of rooms of the house (X)
For a sample of n=64 houses the simple linear regression was estimated:
^Y= 74.80 + 24.93X
Range of X: 5 - 11
Range of Y: 160 - 300 ($ thousands of dollars)
Interpretation of the estimates of the y-intercept and the slope
y-intercept:
74.80 thousand dollars is the estimated average value of a house in a section of the county East Meadow when the house has zero rooms.
Slope:
24.93 [tex]\frac{thousand dollars}{rooms}[/tex] is the modification of the estimated average value of a house in a section of the county East Meadow when the number of rooms increases on one.
I hope this helps!
What is the range of the function in the table
X Y
1 2
2 4
3 3
4 2
A) (1,2,3,4)
B) (1,2) (2,4) (3,3) (4,2)
C) (1,2)
D) (2,3,4)
Answer:
D. (2, 3, 4)
Step-by-step explanation:
The range is the y values. The y values, in numerical order, range from 2 to 4. The 2s do not need to be repeated.
Please answer this correctly
Answer:
Set the height up to 4
Step-by-step explanation:
Since there are 4 numbers between 1-5, set the height up to 4
Answer:
4 temperature recordings.
Step-by-step explanation:
2, 2, 4, 5
There are 4 recordings in the range of 1-5°C.
What’s the correct answer for this question?
Answer:
C:
Step-by-step explanation:
In a circle, the measure of an inscribed angle is half the measure of the central angle with the same intercepted arc
So
AQD = ARC AD/2
<AQD = 78/2
<AQD = 39°
round 3, 942,588 to the nearest thousand
Answer:
3, 943,000
Step-by-step explanation:
3, 942,588
The 2 is in the thousands place
We look at the hundreds place
There is a 5, that means we round up
2 becomes a 3
3, 943,000
NOT SURE NEED HELP PLEASE
Answer:
bh
6, 17
102
51
Step-by-step explanation:
Answer:
1/2 (bh)
1/2(17)(6)
51
The answer and how to solve it.
Answer:
B
Step-by-step explanation:
Peter, Gordon and Gavin share £36 in a ratio 2:1:1. How much money does each person get?
Answer:
Peter gets 18£
Gordon and Gavin each get 9£
Answer:
peter = 18 Gordon = 9 Gavin = 9
Step-by-step explanation:
2+1+1 = 4
36 div 4 = 9
2 times 9 = 18
1 times 9 = 9
The histogram to the right represents the weights (in pounds) of members of a certain high-school debate team. What is the class width? What are the approximate lower and upper class limits of the first class? The class width is_______.
Answer:
Class width = 20
Approximate lower class limit of the first class = 110
Approximate Upper class limit of the first class = 119
Step-by-step Explanation:
The class width of the histogram attached below can be gotten by finding the difference between successive lower class limits.
Thus, class width = 130 - 110 = 20
The approximate lower class limit of the first class is the lowest score we have in the first class = 110
The approximate upper class limit of the first class is the closest highest score that fall within the first class and is below the lower limit of the second class. Thus approximate upper class limit of the first class = 129
What is the measure of angle L in parallelogrami LMNO?
20°
30°
40°
50°
Answer:
40°
Step-by-step explanation:
2x = 3x - 20 add like terms
x = 20 and angle l is equal to 3x minus 20 so 3 × 20 - 20 = 40°
A baseball player comes up to bat 3 times during a league game. He either gets a hit or gets an out. What is the probability that the player gets 3 hits in the three bats ?
Answer:
Since there are 2 possibilities for each bat (hit or out), the amount of total possibilities is 2 * 2 * 2 = 8. There is only one possibility out of those eight that gives us three hits, therefore the probability is 1 / 8 or 0.125.
Luggage checked-in at Airline A arrives on time to its intended destination with a probability of 0.63. In a random sample of 2000 bags, what would be the mean number of bags (out of the 2000) that arrive on time to its intended destination. Also find the standard deviation. Group of answer choices
Answer:
The mean number of bags that arrive on time to its intended destination is 1260 with a standard deviation of 21.59.
Step-by-step explanation:
For each bag, there are only two possible outcomes. Either it arrives on time to it's intended destination, or it does not. The probability of a bag arriving on time is independent of other bags. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
Luggage checked-in at Airline A arrives on time to its intended destination with a probability of 0.63.
This means that [tex]p = 0.63[/tex]
In a random sample of 2000 bags
This means that [tex]n = 2000[/tex]
Mean and standard deviation of the number of bags that arrive on time to its intended destination:
[tex]E(X) = np = 2000*0.63 = 1260[/tex]
[tex]\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{2000*0.63*0.37} = 21.59[/tex]
The mean number of bags that arrive on time to its intended destination is 1260 with a standard deviation of 21.59.
which one of the following solids produces these two-dimensional shape when sliced horizontally?
Answer:
D
Step-by-step explanation:
Which of the following expressions represents "the sum of n and the sum of 8 and 6"? n(8 + 6) n + (8 + 6) (n + 6)8
What’s the correct answer for this question? Select all that Apply
Answer:
B and G
Step-by-step explanation:
Square and rectangle
Martin wants to use coordinate geometry to prove that the opposite sides of
a rectangle are congruent. He places parallelogram ABCD in the coordinate
plane so that A is (0,0), B is (a,0), Cis (a, b), and Dis (0, b).
What formula can he use to determine the distance from point D to point A?
Answer:
Option (B)
Step-by-step explanation:
Coordinates of the vertices of the rectangle were A(0, 0), B(a, 0), C(a, b) and D(0, b)
Formula to determine the distance between two points with the vertices (x, y) and (x', y') is,
d = [tex]\sqrt{(x-x')^2+(y-y')^2}[/tex]
For the length of AD,
AD = [tex]\sqrt{(0-0)^2+(b-0)^2}[/tex]
= [tex]\sqrt{b^2}[/tex]
= b
Therefore, Option (B) will be the answer.
Given that f(x) = x² + 4x, evaluate f(-2).
Answer:
-4
Step-by-step explanation:
resuelve las siguientes ecuaciones tales que 0° ≤ x ≤ 360°
sen x=sen (π/2-x)
cos x + 2 sen x= 2
csc x = sec x
2 cos x * tan x -1 = 0
4 cos2 x = 3 - 4 cos x
Answer:
4cos=2X
X=3-4COS
X=-1
1. Determine the value of 'p' in the equation 4p = 48
2. Simplify the fraction 60/144
3. What is the surface area of a cube with side lengths of 3cm?
1) sorry i don't know =(
2)- 5/12 is the simplified fraction for 60/144.
3)A=54cm²
Find the function y1 of t which is the solution of 121y′′+110y′−24y=0 with initial conditions y1(0)=1,y′1(0)=0. y1= Note: y1 is a linear combination of the two independent solutions of this differential equation that you found first. You are not being asked for just one of these. You will need to determine the values of the two constant parameters c1 and c2. Similarly for finding y2 below. Find the function y2 of t which is the solution of 121y′′+110y′−24y=0 with initial conditions y2(0)=0,y′2(0)=1. y2= Find the Wronskian W(t)=W(y1,y2). W(t)= Remark: You can find W by direct computation and use Abel's theorem as a check. You should find that W is not zero and so y1 and y2 form a fundamental set of solutions of 121y′′+110y′−24y=0.
Answer:
Step-by-step explanation:
The original equation is [tex]121y''+110y'-24y=0[/tex]. We propose that the solution of this equations is of the form [tex] y = Ae^{rt}[/tex]. Then, by replacing the derivatives we get the following
[tex]121r^2Ae^{rt}+110rAe^{rt}-24Ae^{rt}=0= Ae^{rt}(121r^2+110r-24)[/tex]
Since we want a non trival solution, it must happen that A is different from zero. Also, the exponential function is always positive, then it must happen that
[tex]121r^2+110r-24=0[/tex]
Recall that the roots of a polynomial of the form [tex]ax^2+bx+c[/tex] are given by the formula
[tex] x = \frac{-b \pm \sqrt[]{b^2-4ac}}{2a}[/tex]
In our case a = 121, b = 110 and c = -24. Using the formula we get the solutions
[tex]r_1 = -\frac{12}{11}[/tex]
[tex]r_2 = \frac{2}{11}[/tex]
So, in this case, the general solution is [tex]y = c_1 e^{\frac{-12t}{11}} + c_2 e^{\frac{2t}{11}}[/tex]
a) In the first case, we are given that y(0) = 1 and y'(0) = 0. By differentiating the general solution and replacing t by 0 we get the equations
[tex]c_1 + c_2 = 1[/tex]
[tex]c_1\frac{-12}{11} + c_2\frac{2}{11} = 0[/tex](or equivalently [tex]c_2 = 6c_1[/tex]
By replacing the second equation in the first one, we get [tex]7c_1 = 1 [/tex] which implies that [tex] c_1 = \frac{1}{7}, c_2 = \frac{6}{7}[/tex].
So [tex]y_1 = \frac{1}{7}e^{\frac{-12t}{11}} + \frac{6}{7}e^{\frac{2t}{11}}[/tex]
b) By using y(0) =0 and y'(0)=1 we get the equations
[tex] c_1+c_2 =0[/tex]
[tex]c_1\frac{-12}{11} + c_2\frac{2}{11} = 1[/tex](or equivalently [tex]-12c_1+2c_2 = 11[/tex]
By solving this system, the solution is [tex]c_1 = \frac{-11}{14}, c_2 = \frac{11}{14}[/tex]
Then [tex]y_2 = \frac{-11}{14}e^{\frac{-12t}{11}} + \frac{11}{14} e^{\frac{2t}{11}}[/tex]
c)
The Wronskian of the solutions is calculated as the determinant of the following matrix
[tex]\left| \begin{matrix}y_1 & y_2 \\ y_1' & y_2'\end{matrix}\right|= W(t) = y_1\cdot y_2'-y_1'y_2[/tex]
By plugging the values of [tex]y_1[/tex] and
We can check this by using Abel's theorem. Given a second degree differential equation of the form y''+p(x)y'+q(x)y the wronskian is given by
[tex]e^{\int -p(x) dx}[/tex]
In this case, by dividing the equation by 121 we get that p(x) = 10/11. So the wronskian is
[tex]e^{\int -\frac{10}{11} dx} = e^{\frac{-10x}{11}}[/tex]
Note that this function is always positive, and thus, never zero. So [tex]y_1, y_2[/tex] is a fundamental set of solutions.
Multiply or divide as indicated x^10/x^4
Answer:
X^6
Step-by-step explanation:
3(5 − 2 x) = −2(6 – 3 x) − 10 x
Answer:
15-6x= -12-4x
15-2x= -12
-2x= -27
x= -13.5
Step-by-step explanation:
What is the value of -(3/4) to the power of -4
The answer would be -3 13/81 (simplified)
The Hartnett Corporation manufactures baseball bats with Pudge Rodriguez's autograph stamped on them. Each bat for $35 and has a variable cost of $22. there are $97,500 in fixed costs involved in the production process.
Find the sales (in units) needed to earn a profit of $300,000.
Answer:
Find the sales (in units) needed to earn a profit of $262,500
Step-by-step explanation:
hope this is helpful to you bro
Express the following ratio in it’s simplest form.
25:30
Answer:
5/6
Step-by-step explanation:
Find the factor that divides both numbers...
25/5=5
30/5=6
5/6 is the simplified ratio
P.S. Please give me brainliest, i have only have two!
Answer:
1/3:1/4
Step-by-step explanation:
203/259
write in simplest form
2 hours to 45 seconds
Express ratio
15:1
simplest form
1/3:1/4
ASAP! GIVING BRAINLIEST! Please read the question THEN answer CORRECTLY! NO guessing. I say no guessing because people usually guess on my questions.
Answer:
G(x) = x^2 -10x +25
Step-by-step explanation:
To translate F(x) 5 units to the right, replace x with (x-5).
G(x) = F(x-5) = (x -5)^2
G(x) = x^2 -10x +25
Can someone plz help me solved this problem I need help ASAP plz help me! Will mark you as brainiest!
Answer:
-1, 1
13, 15
Step-by-step explanation:
x and x+2 are the integers
x*(x+2)= 7(x+x+2) -1x²+2x= 14x+14-1x² - 12x -13= 0Roots of the quadratic equation are: -1 and 13.
So the integers pairs are: -1, 1 and 13, 15
