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[tex]5.[/tex]
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Suppose scores on exams in statistics are normally distributed with an unknown population mean and a population standard deviation of three points. A random sample of 36 scores is taken and gives a sample mean of 68. Find a 85 % confidence interval estimate for the population mean exam score. Explain what the confidence interval means
this the answer of queastions
Step-by-step explanation:
67.18,68.82
Let mu be the true population mean of statistics exam scores. We have a large random samples of n=36 scores with a sample mean of 68.we know that the population standard deviation is sigma=3.A pivotal quantity is 3^sqrt(36)=(3/6)=68(1/2) which is approximately normally distributed. Therefore the 85%confidence interval is 68-(1/2)(1.6449), 68+(1/2)(1.6449) i.e (67.18,68.82)
A shop sells a particular of video recorder. Assuming that the weekly demand for the video recorder is a Poisson variable with the mean 3, find the probability that the shop sells. . (a) At least 3 in a week. (b) At most 7 in a week. (c) More than 20 in a month (4 weeks).
Answer:
a) 0.5768 = 57.68% probability that the shop sells at least 3 in a week.
b) 0.988 = 98.8% probability that the shop sells at most 7 in a week.
c) 0.0104 = 1.04% probability that the shop sells more than 20 in a month.
Step-by-step explanation:
For questions a and b, the Poisson distribution is used, while for question c, the normal approximation is used.
Poisson distribution:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:
[tex]P(X = x) = \frac{e^{-\lambda}*\lambda^{x}}{(x)!}[/tex]
In which
x is the number of successes
e = 2.71828 is the Euler number
[tex]\lambda[/tex] is the mean in the given interval.
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.
The Poisson distribution can be approximated to the normal with [tex]\mu = \lambda, \sigma = \sqrt{\lambda}[/tex], if [tex]\lambda>10[/tex].
Poisson variable with the mean 3
This means that [tex]\lambda= 3[/tex].
(a) At least 3 in a week.
This is [tex]P(X \geq 3)[/tex]. So
[tex]P(X \geq 3) = 1 - P(X < 3)[/tex]
In which:
[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]
Then
[tex]P(X = x) = \frac{e^{-\lambda}*\lambda^{x}}{(x)!}[/tex]
[tex]P(X = 0) = \frac{e^{-3}*3^{0}}{(0)!} = 0.0498[/tex]
[tex]P(X = 1) = \frac{e^{-3}*3^{1}}{(1)!} = 0.1494[/tex]
[tex]P(X = 2) = \frac{e^{-3}*3^{2}}{(2)!} = 0.2240[/tex]
So
[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0498 + 0.1494 + 0.2240 = 0.4232[/tex]
[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 1 - 0.4232 = 0.5768[/tex]
0.5768 = 57.68% probability that the shop sells at least 3 in a week.
(b) At most 7 in a week.
This is:
[tex]P(X \leq 7) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7)[/tex]
In which
[tex]P(X = x) = \frac{e^{-\lambda}*\lambda^{x}}{(x)!}[/tex]
[tex]P(X = 0) = \frac{e^{-3}*3^{0}}{(0)!} = 0.0498[/tex]
[tex]P(X = 1) = \frac{e^{-3}*3^{1}}{(1)!} = 0.1494[/tex]
[tex]P(X = 2) = \frac{e^{-3}*3^{2}}{(2)!} = 0.2240[/tex]
[tex]P(X = 3) = \frac{e^{-3}*3^{3}}{(3)!} = 0.2240[/tex]
[tex]P(X = 4) = \frac{e^{-3}*3^{4}}{(4)!} = 0.1680[/tex]
[tex]P(X = 5) = \frac{e^{-3}*3^{5}}{(5)!} = 0.1008[/tex]
[tex]P(X = 6) = \frac{e^{-3}*3^{6}}{(6)!} = 0.0504[/tex]
[tex]P(X = 7) = \frac{e^{-3}*3^{7}}{(7)!} = 0.0216[/tex]
Then
[tex]P(X \leq 7) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) = 0.0498 + 0.1494 + 0.2240 + 0.2240 + 0.1680 + 0.1008 + 0.0504 + 0.0216 = 0.988[/tex]
0.988 = 98.8% probability that the shop sells at most 7 in a week.
(c) More than 20 in a month (4 weeks).
4 weeks, so:
[tex]\mu = \lambda = 4(3) = 12[/tex]
[tex]\sigma = \sqrt{\lambda} = \sqrt{12}[/tex]
The probability, using continuity correction, is P(X > 20 + 0.5) = P(X > 20.5), which is 1 subtracted by the p-value of Z when X = 20.5.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{20 - 12}{\sqrt{12}}[/tex]
[tex]Z = 2.31[/tex]
[tex]Z = 2.31[/tex] has a p-value of 0.9896.
1 - 0.9896 = 0.0104
0.0104 = 1.04% probability that the shop sells more than 20 in a month.
The probability of the selling the video recorders for considered cases are:
P(At least 3 in a week) = 0.5768 approximately.P(At most 7 in a week) = 0.9881 approximately.P( more than 20 in a month) = 0.0839 approximately.What are some of the properties of Poisson distribution?Let X ~ Pois(λ)
Then we have:
E(X) = λ = Var(X)
Since standard deviation is square root (positive) of variance,
Thus,
Standard deviation of X = [tex]\sqrt{\lambda}[/tex]
Its probability function is given by
f(k; λ) = Pr(X = k) = [tex]\dfrac{\lambda^{k}e^{-\lambda}}{k!}[/tex]
For this case, let we have:
X = the number of weekly demand of video recorder for the considered shop.
Then, by the given data, we have:
X ~ Pois(λ=3)
Evaluating each event's probability:
Case 1: At least 3 in a week.
[tex]P(X > 3) = 1- P(X \leq 2) = \sum_{i=0}^{2}P(X=i) = \sum_{i=0}^{2} \dfrac{3^ie^{-3}}{i!}\\\\P(X > 3) = 1 - e^{-3} \times \left( 1 + 3 + 9/2\right) \approx 1 - 0.4232 = 0.5768[/tex]
Case 2: At most 7 in a week.
[tex]P(X \leq 7) = \sum_{i=0}^{7}P(X=i) = \sum_{i=0}^{7} \dfrac{3^ie^{-3}}{i!}\\\\P(X \leq 7) = e^{-3} \times \left( 1 + 3 + 9/2 + 27/6 + 81/24 + 243/120 + 729/720 + 2187/5040\right)\\\\P(X \leq 7) \approx 0.9881[/tex]
Case 3: More than 20 in a month(4 weeks)
That means more than 5 in a week on average.
[tex]P(X > 5) = 1- P(X \leq 5) =\sum_{i=0}^{5}P(X=i) = \sum_{i=0}^{5} \dfrac{3^ie^{-3}}{i!}\\\\P(X > 5) = 1- e^{-3}( 1 + 3 + 9/2 + 27/6 + 81/24 + 243/120)\\\\P(X > 5) \approx 1 - 0.9161 \\ P(X > 5) \approx 0.0839[/tex]
Thus, the probability of the selling the video recorders for considered cases are:
Learn more about poisson distribution here:
https://brainly.com/question/7879375
I'm interval notation please
9514 1404 393
Answer:
(-2, 4]
Step-by-step explanation:
-21 ≤ -6x +3 < 15 . . . . given
-24 ≤ -6x < 12 . . . . . . subtract 3
4 ≥ x > -2 . . . . . . . . . . divide by -6
In interval notation, the solution is (-2, 4].
__
Interval notation uses a square bracket to indicate the "or equal to" case--where the end point is included in the interval. A graph uses a solid dot for the same purpose. When the interval does not include the end point, a round bracket (parenthesis) or an open dot are used.
The midpoint of has coordinates of (4, -9). The endpoint A has coordinates (-3, -5). What are the coordinates of B?
9514 1404 393
Answer:
(11, -13)
Step-by-step explanation:
If midpoint M is halfway between A and B:
M = (A +B)/2
Then B is ...
B = 2M -A
B = 2(4, -9) -(-3, -5) = (8+3, -18+5)
B = (11, -13)
Answer:
Use the midpoint formula:
[tex]midpoint=(\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2})[/tex]
Endpoint A = (x₁, y₁) = (-3, -5)Endpoint B = (x₂, y₂)Midpoint = (4, -9)Substitute in the values:
[tex](4, -9)=(\frac{-3+x_{2}}{2} +\frac{-5+y_{2}}{2} )[/tex]
[tex]4=\frac{-3+x_{2}}{2} \\4(2)=-3+x_{2}\\8+3=x_{2}\\x_{2}=11[/tex] [tex]-9=\frac{-5+y_{2}}{2} \\(-9)(2)=-5+y_{2}\\-18+5=y_{2}\\y_{2}=-13[/tex]
Therefore, Point B = (11, -13)
find the quotient 1/5 / (-5/7) =
Answer:
-7/25
Step-by-step explanation:
1/5 ÷ (-5/7)
Copy dot flip
1/5 * -7/5
-7/25
Given: AABC, AC = 5
m C = 90°
m A= 22°
Find: Perimeter of AABC
A
C
B
9514 1404 393
Answer:
perimeter ≈ 12.4 units
Step-by-step explanation:
The side adjacent to the angle is given. The relationships useful for the other two sides are ...
Tan = Opposite/Adjacent
Cos = Adjacent/Hypotenuse
From these, we have ...
opposite = 5·tan(22°) ≈ 2.02
hypotenuse = 5/cos(22°) ≈ 5.39
Then the perimeter is ...
P = a + b + c = 2.02 + 5 + 5.39 = 12.41
The perimeter of ∆ABC is about 12.4 units.
Use absolute value to express the distance between -12 and -15 on the number line
A: |-12-(-15)|= -37
B: |-12-(-15)|= -3
C: |-12-(-15)|= 3
D: |-12-(-15)|= 27
the mean salary if of 5 employees is $35900. the median is $37000. the mode is $382000. If the median payed employee gets a $3100 raise, then…
New median:
New mode:
Answer:
Step-by-step explanation:
New median:40100
New mode:385100
Which of the fractions below are less than 2/5? Select two.
Answer:
1/8 is less than
Step-by-step explanation:
i dont see any fractions below gona have to edit your answer
Most of the heat loss for outdoor swimming pools is due to surface
evaporation. So, the greater the area of the surface of the pool, the greater
the heat loss. For a given perimeter, which surface shape would be more
efficient at retaining heat: a circle or a rectangle? Justify your answer.
Answer:
rectangle
Step-by-step explanation:
Perimeter of 20 feet
rectangle (square is technically a rectangle):
sides 5 and 5
5*5 = 25ft²
Circle:
20/(2π) = 3.18309...
3.1809...²π = 31.831ft²
Max area of rectangle (i.e. square) has a smaller area than a circle.
Because the P-value is ____ than the significance level 0.05, there ____ sufficient evidence to support the claim that there is a linear correlation between lemon imports and crash fatality rates for a significance level of α= 0.05.
Do the results suggest that imported lemons cause carfatalities?
a. The results suggest that an increase in imported lemons causes car fatality rates to remain the same.
b. The results do not suggest any cause-effect relationship between the two variables.
c. The results suggest that imported lemons cause car fatalities.
d. The results suggest that an increase in imported lemons causes in an increase in car fatality rates.
Answer:
H0 : correlation is equal to 0
H1 : correlation is not equal to 0 ;
Pvalue < α ;
There is sufficient evidence
r = 0.945 ;
Pvalue = 0.01524
Step-by-step explanation:
Given the data :
Lemon_Imports_(x) Crash_Fatality_Rate_(y)
230 15.8
264 15.6
359 15.5
482 15.3
531 14.9
Using technology :
The regression equation obtained is :
y = 16.3363-0.002455X
Where, slope = - 0.002455 ; Intercept = 16.3363
The Correlation Coefficient, r = 0.945
H0 : correlation is equal to 0
H1 : correlation is not equal to 0 ;
The test statistic, T:
T = r / √(1 - r²) / (n - 2)
n = 5 ;
T = 0.945 / √(1 - 0.945²) / (5 - 2)
T = 0.945 / 0.1888341
T = 5.00439
The Pvalue = 0.01524
Since Pvalue < α ; Reject the Null and conclude that there is sufficient evidence to support the claim.
plez halppp mehh ;-;
Answer:
False
True
True
Step-by-step explanation:
Angle 1 cannot be equal to angle 4. Even by just viewing one can see that they can't be equal.
Angle 1 and 2 when combined give a 90 degree angle going from a to c.
Angle 3 and 4 form a 180 degree angle.
HOPE THIS HELPED
Emily, Yani and Joyce have a total of 3209 stickers. Yani has 2 times
as many stickers as Joyce. Emily has 279 more stickers than Yani. How
many more stickers does Emily have than Joyce?
Answer:
279+x
Step-by-step explanation:
Emily + Yani + Joyce=3209 stickers
if Yani has 2 times as many stickers as Joyce:this statement states that Joyce has x stickers and Yani has 2x stickers because x multiplied by 2"Emily has 279 more stickers than Yani":therefore the equation for Emily will be ;279+2xhow many stickers does Emily have than Joyce:
(279+2x)-(x)
279+2x-x
=279+x
the age of furaha is 1/2 of the age of her aunt if the sum of their ages is 54 years. find the age of her aunt
Answer:
I think it is twenty seven
3. Find the least common denominator for the group of denominators using the method of prime numbers. 45, 75, 63
We have to find LCM
3 | 45,75,63
3 | 15,25,21
5 | 5,25,7
5 | 1,5,7
7 | 1,1,7
LCM=3×3×5×5×7=1575
The least common denominator for the group of denominators using the method of prime numbers is 1575.
What is least common multiple?LCM stands for Least Common Multiple. It is a method to find the smallest common multiple between any two or more numbers. A factor is one of the numbers that multiplies by a whole number to get that number.
For the given situation,
The numbers are 45, 75, 63
Prime factors of 45 = [tex]3,3,5[/tex]
Prime factors of 75 = [tex]3,5,5[/tex]
Prime factors of 63 = [tex]3,3,7[/tex]
Then the LCM can be found by, first take the common factors then multiple the remaining factors as,
⇒ [tex](3)(3)(5)(5)(7)[/tex]
⇒ [tex]1575[/tex]
Hence we can conclude that the least common denominator for the group of denominators using the method of prime numbers is 1575.
Learn more about least common multiple here
https://brainly.com/question/24859913
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Given the function f(x) = -5x + 2, find the range ofly for x = -1, 0, 1.
O 7, 2, -3
O 7, 2, 3
O-7, -2, 3
0-7, -2, -3
Answer:
A
Step-by-step explanation:
f(-1)=7, f(0)=2, f(1)=-3
Can someone please help solve this equation thank you
Answer:
A and B
Step-by-step explanation:
Both points are in the shaded/blue zone
I hope this helps!
pls ❤ and give brainliest pls
Answer:
Yea both A and B are correct.
Step-by-step explanation:
if you can see you can put (-12,0) inside the shaded triangle also for (-10,1)
you can give brainlist to the person above :D
a certain number plus two is five find the number
x=3
Step-by-step explanation:
x+2=5
x=5-2
x=3
A chocolate chip cookie manufacturing company recorded the number of chocolate chips in a sample of 60 cookies. The mean is 22.36 and the standard deviation is2.97 . Construct a 80% confidence interval estimate of the standard deviation of the numbers of chocolate chips in all such cookies.
Answer:
2.665 < σ < 3.379
Step-by-step explanation:
Given :
s = 2.97
Sample size, n = 60
α = 80%
χ² Critical value (two - tailed), df = (60-1) = 59
χ² = 45.577 ; χ² = 73.279
The 80% confidence interval for the standard deviation :
s * √(n - 1) / χ² critical
2.97 * √(60 - 1) / 73.279 < σ < 2.97 * √(60 - 1) / 45.577
2.665 < σ < 3.379
Show that Reſiz) = -Im(z)
Step-by-step explanation:
[tex]re(i(x + yi) = - im(x + yi) \\ re(xi - y) = - im(x + yi) \\ - y = - (y) \\ - y = - y \\ proved \: is \: correct[/tex]
Lainey is looking for a new apartment and her realtor keeps calling her with new listings . The calls only take a few minutes , but a few minutes here and there are really starting to add up . She's having trouble concentrating on her work . What should Lainey do ? a ) Tell her realtor she can only receive text messages b ) Limit the time spent on each call c ) Turn off her phone until she is on a break d ) Call her realtor back when customers won't see her on the phone
Answer:
c ) Turn off her phone until she is on a break
Is this the correct answer?
Answer:
25.40
Step-by-step explanation:
tickets ( 2 at 10.95 each) = 2* 10.95 = 21.90
popcorn ( 1 at 7.50) = 7.50
Total cost before discount
21.90+7.50=29.40
subtract the discount
29.40-4.00 =25.40
Answer:
Yep! That's correct!
Step-by-step explanation:
We know that Marilyn and her sister are each getting a ticket that cost $10.95. They are also getting a $7.50 popcorn to share. Let's add those values up.
(10.95 * 2) + 7.50 {Multiply 10.95 by 2 to get 21.90.}
21.90 + 7.50 {Add 7.50 to 21.90 to get 29.40}
$29.40 (without the credit) in toal
A credit on a movie reward card functions as a discount, so what we need to do next is subtract 4 from 29.40. That will get us $25.40 as the total cost.
After doing the math, I can deduce that your answer is correct!
5 Cece draws these two figures to prove there is more
than one parallelogram with a 40° angle between a
2-cm side and a 6-cm side. Is Cece correct? Explain.
2 cm
40
4.
2 cm
Answer:
chash greatly ta 45uerywryrsyrsyrs
If 1100 square centimeters of material is available to make a box with a square base and an open top, find the largest possible volume of the box. Round to two decimal places if necessary.
volume= a^2 * h
area= a^2+4ah
take the second equation, solve for h
4ah=1100-a^2
h=1100/4a -1/4 a now put that expression in volume equation for h.
YOu now have a volume expression as function of a.
take the derivative, set to zero, solve for a. Then put that value back into the volume equation, solve for Volume.
Cited from jiskha
look at the image below
Answer:
117.8
Step-by-step explanation:
Surface area = πr²+πrl (whee r = radius and l = slant height)
= π×3²+π×3×9.5
= 75π/2
= 117.8
use quadratic formula to solve the following equation
9514 1404 393
Answer:
x = 2 or x = 9
Step-by-step explanation:
To use the quadratic formula, we first need the equation in standard form for a quadratic. We can get there by multiplying the equation by 3(x -3).
2(3) +4(3(x -3)) = (x +4)(x -3)
6 +12x -36 = x² +x -12
x² -11x +18 = 0
Using the quadratic formula to find the solutions, we have ...
[tex]x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}=\dfrac{-(-11)\pm\sqrt{(-11)^2-4(1)(18)}}{2(1)}\\\\x=\dfrac{11\pm\sqrt{49}}{2}=\{2,9\}[/tex]
The solutions are x=2 and x=9.
(2+1/2) (2^2-1+1/4) find the expression in the form of cubes and differences of two terms.
Answer:
Consider the following identity:
a³ - b³ = (a + b)(a² - ab + b²)Let a = 2, b = 1/2
(2 + 1/2)(2² - 2*1/2 + 1/2²) = 2³ - (1/2)³ =8 - 1/8Use the algebraic identity given below
[tex]\boxed{\sf a^3-b^3=(a+b)(a^2-ab+b^2)}[/tex]
[tex]\\ \sf\longmapsto (2+\dfrac{1}{2})(2^2-1+\dfrac{1}{4})[/tex]
[tex]\\ \sf\longmapsto (2+\dfrac{1}{2})(2^2-2\times \dfrac{1}{2}+\dfrac{1}{2}^2)[/tex]
Here a =2 and b=1/2[tex]\\ \sf\longmapsto 2^3-\dfrac{1}{2}^3[/tex]
[tex]\\ \sf\longmapsto 8-\dfrac{1}{8}[/tex]
please help me with geometry
Answer:
x = 5Step-by-step explanation:
triangol BCD = triangle BDA
so
3x - 1 = 34 - 2x
5x = 35
x = 35 : 5
x = 5Answer:
x = 7
Step-by-step explanation:
BD is an angle bisector , so
∠ ABD = ∠ DBC , that is
3x - 1 = 34 - 2x ( add 2x to both sides )
5x - 1 = 34 ( add 1 to both sides )
5x = 35 ( divide both sides by 5 )
x = 7
NEED HALP!!! Find the ordered pair $(s,t)$ that satisfies the system
Answer:
(-8/7 ; 5/7)
Step-by-step explanation:
5t + 1/2s = 3 - - - (1)
3t - 6s = 9 - - - - - (2)
Multiply (1) by 12 and (2) by 1
Add the result to eliminate s
60t + 6s = 36
3t - 6s = 9
____________
63t = 45
t = 45 / 63
t = 5/7
Put t = 5/7 in either (1) or (2) to obtain the value of s
3(5/7) - 6s = 9
15/7 - 6s = 9
-6s = 9 - 15/7
-6s = (63 - 15)/7
-6s = 48/7
s = 48/7 * - 1/6
s = - 8/7
Solve this equation for x. Round your answer to the nearest hundredth.
1 = In(x + 7)
Answer:
[tex]\displaystyle x \approx -4.28[/tex]
General Formulas and Concepts:
Pre-Algebra
Equality PropertiesAlgebra II
Natural logarithms ln and Euler's number eStep-by-step explanation:
Step 1: Define
Identify
[tex]\displaystyle 1 = ln(x + 7)[/tex]
Step 2: Solve for x
[Equality Property] e both sides: [tex]\displaystyle e^1 = e^{ln(x + 7)}[/tex]Simplify: [tex]\displaystyle x + 7 = e[/tex][Equality Property] Isolate x: [tex]\displaystyle x = e - 7[/tex]Evaluate: [tex]\displaystyle x = -4.28172[/tex]e^1 = x+7
e - 7 = x
x = -4.28
