Use the information provided to determine a 95% confidence interval for the population variance. A researcher was interested in the variability in service time (in hours) spent by mechanics fixing the same automotive problem. A random sample was taken resulting in a sample of size 20 from a substantial file of reported experience. The summary statistics are as follows: n = 20, sample mean = 13.8 hours, sample standard deviation = 3.9 hours. Assume service time follows a normal distribution. Round to two decimal places.

Answer:

[tex]\pi[/tex] radian

Step-by-step explanation:

We know that angle for a full circle is 2[tex]\pi[/tex]

In the given figure shape is semicircle

hence,

angle for semicircle will be half of angle of full circle

thus, angle for given figure = half of  angle for a full circle = 1/2 * 2[tex]\pi[/tex] = [tex]\pi[/tex]

Thus, answer is [tex]\pi[/tex] radian

alternatively, we also know that angle for a straight line is 180 degrees

and 180 degrees is same as [tex]\pi[/tex] radian.

Step-by-step explanation:

Just sub 4 into where n is

Answer:

12.1%

Step-by-step explanation:

Given that:

Mean (μ) = 20.2 grams and standard deviation (σ) = 0.18 grams.

The z score is a score used to determine the number of standard deviations by which the raw score is above or below the mean. A positive z score means  that the raw score is above the mean and a negative z score means that the raw score is below the mean. It is given by:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

a) For x < 19.99 g:

[tex]z=\frac{x-\mu}{\sigma}\\\\z=\frac{19.99-20.2}{0.18} \\\\z=-1.17[/tex]

From the normal distribution table, P(x < 19.99) = P(z < -1.17) = 0.1210 = 12.1%

The probability that a randomly chosen mouse has a mass of less than 19.99 grams is 12.1%

Looks like either [tex]f''(x)=4x^2[/tex] or [tex]f''(x)=\frac4{x^2}[/tex]...

In the first case, integrate both sides twice to get

[tex]f''(x)=4x^2\implies f'(x)=\dfrac43x^3+C_1\implies f(x)=\dfrac13x^4+C_1x+C_2[/tex]

Then the initial conditions give

[tex]f'(1)=2\implies 2=\dfrac43\cdot1^3+C_1\implies C_1=\dfrac23[/tex]

[tex]f(1)=5\implies 5=\dfrac13\cdot1^4+C_1\cdot1+C_2\implies C_2=4[/tex]

so that the particular solution is

[tex]f(x)=\dfrac{x^4}3+\dfrac{2x}3+4[/tex]

If instead [tex]f''(x)=\frac4{x^2}[/tex], we have

[tex]f''(x)=\dfrac4{x^2}\implies f'(x)=-\dfrac4x+C_1\implies f(x)=-4\ln|x|+C_1x+C_2[/tex]

[tex]f'(1)=2\implies 2=-\dfrac41+C_1\implies C_1=6[/tex]

[tex]f(1)=5\implies 5=-4\ln|1|+C_1\cdot1+C_2\implies C_2=-1[/tex]

[tex]\implies f(x)=-4\ln|x|+6x-1[/tex]

Answer:

-6x² -4x -16

Step-by-step explanation:

be watchful of signs to avoid making errors

Answer:

  71°

Step-by-step explanation:

Consider triangle BDH. x is the external angle that is remote to internal angles B and D, so is equal to their sum:

  x° = 41° +30°

  x° = 71°

Answer:

10.125

Step-by-step explanation:

Hello!

To find this we first have to convert the percentage to a decimal

We do this by moving the decimal point two times left

75.0% = 0.75

Now we multiply this by the number

13.5 * 0.75 = 10.125

The answer is 10.125

Hope this helps!

Answer:

64

Step-by-step explanation:

Let us consider E_abc to be the event that a, b and c appear on the first, second and third slot of the spin machine.

Now, we are told that each slot has 4 possibilities which are a cherry, a lemon, a star, or a bar when spun.

Thus, from mn rule in probability, the total number of simple events in the sample space is = 4³ = 64

Answer: 0.0546 and 0.9829

Step-by-step explanation:

solution:

= P( 1.50< Z <2.25 )

= P(Z <2.25 ) - P(Z <1.50 )

Using z table,

= 0.9878-0.9332

=0.0546

b.

= P( -2.12< Z <3.73 )

= P(Z <3.73) - P(Z <-2.12 )

Using z table,

= 0.9999-0.0170

=0.9829

Answer:

Correct options are 2, 5 and 7.

Step-by-step explanation:

Consider the given vertices of triangle are A(-3,-3), B(-3,2) and C(1,2).

Distance formula:

[tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

Using distance formula, we get

[tex]AB=\sqrt{(-3-(-3))^2+(2-(-3))^2}[/tex]

[tex]AB=\sqrt{(0)^2+(5)^2}[/tex]

[tex]AB=\sqrt{25}[/tex]

[tex]AB=5[/tex]

Similarly,

[tex]BC=\sqrt{(1-(-3))^2+(2-2)^2}=4[/tex]

[tex]AC=\sqrt{(1-(-3))^2+(2-(-3))^2}=\sqrt{16+25}=\sqrt{41}[/tex]

From the above calculation it is clear that AC>AB and AC>BC.

According to Pythagoras theorem, in a right angle triangle, the square of largest side is equal to the sum of squares of two small sides.

[tex]hypotenuse^2=base^2+perpendicular^2[/tex]

[tex]AC^2=(\sqrt{41})^2=41[/tex]

[tex]AB^2+BC^2=(5)^2+4^2=24+16=41=AC^2[/tex]

So, given triangle is a right angle triangle and AC is its hypotenuse.

Therefore, the correct options are 2, 5 and 7.

Answer:

0.000014

Step-by-step explanation:

The chart is not provided so i will use an example chart to explain the answer. Here is a sample chart:

City X's Population by Age

0-24 years old 33%

25-44 years old 22%

45-64 years old 21%

65 or older 24%

In order to find probability of independent events we find the probability of each event occurring separately and then multiply the calculated probabilities together in the following way:

P(A and B) = P(A) * P(B)

probability that the first 2 are 65 or older

Let A be the event that the first 2 are 65 or older

The probability of 65 or older 24% i.e. 0.24

So the probability that first 2 are 65 or older is:

0.24(select resident 1) * 0.24(select resident 2)

P(A) = 0.24 * 0.24

       = 0.0576

P(A) = 0.0576

probability that the next 3 are 25-44 years old

Let B be the event that the next 3 are 25-44 years old

25-44 years old 22%  i.e. 0.22

So the probability that the next 3 are 25-44 years old is:

0.22 * 0.22* 0.22

P(B) = 0.22 * 0.22 * 0.22

      = 0.010648

P(B) = 0.010648

probability that next 2 are 24 or younger

Let C be the event that the next 2 are 24 or younger

0-24 years old 33% i.e. 0.33

So the probability that the next 2 are 24 or younger is:

0.33 * 0.33

P(C) = 0.33 * 0.33

       = 0.1089

P(C) = 0.1089

probability that last is 45-64 years old

Let D be the event that last is 45-64 years old

45-64 years old 21%  i.e. 0.21

So the probability that last is 45-64 years old is:

0.21

P(D) = 0.21

So probability of these independent events is computed as:

P(A and B and C and D) = P(A) * P(B) * P(C) * P(C)

                                        = 0.0576 * 0.010648  * 0.1089  * 0.21

                                        = 0.000014

Answer: Yes they form a proportion. The given equation is a true equation.

==========================================

Explanation:

The idea is that if we have

a/b = c/d

then that it is the same as

a*d = b*c

This is known as cross multiplication. We'll use this rule to get

15/12 = 4.5/3.6

15*3.6 = 12*4.5

54 = 54

We got the same value on both sides, meaning that the last equation is true. Consequently, it means the first equation is true as well (all three equations are true).

--------

You could also use your calculator to see that

15/12 = 1.25

4.5/3.6 = 1.25

showing that 15/12 = 4.5/3.6 is a true equation and the ratios form a proportion.

Answer:

15/12=4.5/3.6 = True

Step-by-step explanation:

Simplify the following:  Left-hand

15/12

Hint: | Reduce 15/12 to lowest terms. Start by finding the GCD of 15 and 12.

The gcd of 15 and 12 is 3, so 15/12 = (3×5)/(3×4) = 3/3×5/4 = 5/4:

Answer: 5/4

______________________________

Approximate the following:

4.5/3.6

Hint: | Express 4.5/3.6 in decimal form.

4.5/3.6 = 1.25:

Answer:  1.25 = 5/4

Answer:

continuous

Step-by-step explanation:

A quantity like temperature is a continuous random variable. A continuous random variable is different from a discrete random variable because it can take on many values infinitely.

From the question, measuring the Temperature in degrees can take on many different values because there are an uncountable number of possible temperatures that could be taken.

Answer:

Answer to question a = 95.4

Answer to question b = UCL = 96.07

LCL = 94.73

Answer to question c = Process is still in control

Step-by-step explanation:

a. The computation of estimate mean is as shown below:-

= 95.4

b. The computation of Upper Control Limit (UCL) and the Lower Control Limit (LCL) for the manufacturing process is shown below:-

= 95.4 + 0.67082

= 96.07

= 95.4 - 0.67082

= 94.73

c. The explanation is shown below:-

From the above calculation we can see that the sample lies between LCL AND UCL that is (94.73 ,96.07) ,

The Process is still in control

(a)

[tex]\dfrac{\partial f}{\partial x}=x^2\implies f(x,y)=\dfrac{x^3}3+g(y)[/tex]

[tex]\dfrac{\partial f}{\partial y}=\dfrac{\mathrm dg}{\mathrm dy}=y^2\implies g(y)=\dfrac{y^3}3+C[/tex]

[tex]\implies f(x,y)=\dfrac{x^3+y^3}3+C[/tex]

(b)

[tex]\displaystyle\int_C\nabla f\cdot\mathrm d\mathbf r=f(2,8)-f(-1,2)=\boxed{171}[/tex]

Answer:

12c-7d

Step-by-step explanation:

[tex]4c-4d+8c-3d=0\\4c+8c=3d+4d\\12c=7d\\12c-7d[/tex]

===============================================

Explanation:

The terms 4c and 8c are one pair of like terms that combine to 4c+8c = 12c. We add 4 and 8 to get 12, then tack a 'c' at the end

The other pair of like terms are -4d and -3d. They combine to -7d for similar reasoning.

12c and -7d are not like terms, so we can't combine them and we stop here.

-----------

One way to think of combining like terms is consider simplifying 2c+3c. You could say that 2c represents having 2 cups while 3c is having 3 cups. Writing 2c+3c means we start with 2 cups and add on 3 more getting a total of 2+3 = 5 cups. Symbolically we would then write 5c. Therefore 2c+3c = 5c.

Answer: x>3

Step-by-step explanation:

x-5>2

x>+5-2

x>3

Answer:

The standard error decreases and the width of the confidence interval also decreases.

Step-by-step explanation:

The standard error of a distribution (E) is given as:

[tex]E=z_{\frac{\alpha}{2} }*\frac{\sigma}{\sqrt{n} }[/tex]

Where n is the sample size, [tex]z_{\frac{\alpha}{2} }[/tex] is the z score of he confidence and [tex]\sigma[/tex] is the standard deviation.

The sample size is inversely proportional to the standard error. If the sample size is increased and everything else is constant, the standard would decrease since they are inversely proportional to each other. The confidence interval = μ ± E = (μ - E, μ + E). μ is the mean

The width of the confidence interval = μ + E - (μ - E) = μ + E - μ + E = 2E

The width of the confidence interval is 2E, therefore as the sample size increase, the margin of error decrease and since the width of the confidence interval is directly proportional to the margin of error, the width of the confidence interval also decreases.

Answer:

10/7 or 1 3/7. I hope this helps,

Step-by-step explanation:

6 pounds of strawberries and 1 pound of blueberries

I did the quiz

Answer:

Goes on forever.

Step-by-step explanation:

Answer:

see below

Step-by-step explanation:

4,7,12,19

We are adding 3,5,7,9..... each time

The sequence is not arithmetic because we are not adding a constant.  It is not geometric since we are not multiplying by a constant term each time

There is no common difference  or common ratio.

The explicit formula is

an =n^2 +3

The recursive formula is

(n+1)^2 +3 - (n^2 +3)

    n^2 +2n+1+3 - ( n^2+3)

      2n+1

a sub(n+1) = a sub( n) + 2n+1

The 10th term

an      = n^2 +3

Let n=10

an = 10^2+3

    = 100+3

    = 103

summation

see image

since the numbers are increasing and greater than 1 the sum does not exist

Answer: Find answer in the attachment

Step-by-step explanation:

Answer:

38 = JKL

Step-by-step explanation:

JKM = JKL + LKN + NKM

Substituting what we know

104 = JKL + LKN +33

KN  bisects LKM so NKM =  LKN

33 =  LKN

104 = JKL + 33 +33

104 = JKL + 33 +33

Combine like terms

104 = JKL +66

104 - 66 = JKL

38 = JKL

Answer:  ∡JKL=38°

Step-by-step explanation:

KN bidects ∡LKM => ∠KLN=∡NKM=33°

=> ∡LKM=∠KLN+∡NKM=33°+33°=66°

=>∡JKL= ∡JKM-∡LKM= 104°-66°=38°

∡JKL=38°

Answer:

The simplified answer of the given expression is 1.

Step-by-step explanation:

When you see (f + g)(x), then it means that you are going to add f(x) and g(x) together. So, we are going to add the terms together that are given in the problem. We are also given the value of x which is 1. So, we are going to combine this information together so we can simplify the expression.

(f + g)(1)

f(x) = x - 1

g(x) = x²

(f + g)(1) = (1 - 1) + (1²)

Simplify the terms in the parentheses.

(f + g)(1) = 0 + 1

Add 0 and 1.

(f + g)(1) = 1

So, (f + g)(1) will have a simplified answer of 1.

Answer:

The standard error of the sample mean is [tex]\sigma_{\= x } = 0.40[/tex]

Step-by-step explanation:

From the question we are told that

     The population mean is  [tex]\mu = 5.30 \ hours[/tex]

     The population standard deviation is [tex]\sigma = 3.20 \ hours[/tex]

      The sample size is  [tex]n = 64[/tex]

Generally the standard error of the sample mean is mathematically represented as

               [tex]\sigma_{\= x } = \frac{\sigma}{\sqrt{n} }[/tex]

substituting values

                [tex]\sigma_{\= x } = \frac{3.20}{\sqrt{64} }[/tex]

                [tex]\sigma_{\= x } = 0.40[/tex]

Answer:

96

Step-by-step explanation:

From the given information:

At 95% Confidence interval level,Level of significance [tex]\alpha[/tex] 0.05, the value of Z from the standard normal tables = 1.96

Margin of Error = 0.10

Let assume that the estimated proportion = 0.5

therefore; the sample size n can be determined by using the formula: [tex]n =(\dfrac{Z}{E})^2 \times p\times (1-p)[/tex]

[tex]n =(\dfrac{1.96}{0.1})^2 \times 0.5\times (1-0.5)[/tex]

[tex]n =(19.6)^2 \times 0.5\times (0.5)[/tex]

n = 96.04

n [tex]\approx[/tex] 96

Answer:

5443

Step-by-step explanation:

Order of Operations: BPEMDAS

Always left to right.

Step 1: Add 68 and 5042

68 + 5042 = 5110

Step 2: Add 5110 and 333

5110 + 333 = 5443

And we have our answer!

Answer:

Calculated χ² = 13.425

χ² (5,0.025) >14.45 and χ²(5,0.975) <1.24

The given data does not fall in the critical region so we accept H0 and conclude there is no evidence to doubt the color distribution claimed by the website.

Step-by-step explanation:

Color             Blue      Orange     Green    Red   Yellow    Brown

Frequency     30         48              55        66         70         131

Expected      40           40              40        80          80        120

H0:  The bag of plain M&Ms is made up of 10% blue, 10% orange, 10% green, 20% red, 20% yellow, and 30% brown

Ha: The color distribution is not equal to  the distribution stated in the null hypothesis.

Calculate chi square

χ² = (30-40)² /40 + (48-40)²/40 + (55-40)²/40 + (66-80)²/80 + (70-80)²/80 + (131-120)²/120

χ² = 2.5 + 1.6 + 5.625 + 2.45 + 1.25= 13.425

The critical region for χ²  for 5 degrees of freedom with ∝= 0.05 is

χ² (5,0.025) >14.45 and χ²(5,0.975) <1.24

The given data does not fall in the critical region so we accept H0 and conclude there is no evidence to doubt the color distribution claimed by the website.