A consumer group has determined that the distribution of life spans for gas ranges (stoves) has a mean of 15.0 years and a standard deviation of 4.2 years. The distribution of life spans for electric ranges has a mean of 13.4 years and a standard deviation of 3.7 years. Both distributions are moderately skewed to the right. Suppose we take a simple random sample of 35 gas ranges and a second SRS of 40 electric ranges. Which of the following best describes the sampling distribution of the difference in mean life span of gas ranges and electric ranges?
a. Mean = 1.6 years, standard deviation = 7.9 years, shape: moderately right-skewed.
b. Mean = 1.6 years, standard deviation - 0.92 years, shape: approximately Normal.
c. Mean= 1.6 years, standard deviation = 0.92 years, shape: moderately right skewed.
d. Mean =1.6 years, standard deviation =0.40 years, shape: approximately Normal.
e. Mean =1.6 years, standard deviation =0.40 years, shape: moderately right skewed.

Answers

Answer 1

Answer:

b. Mean = 1.6 years, standard deviation - 0.92 years, shape: approximately Normal.

Step-by-step explanation:

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.

Subtraction of normal Variables:

When we subtract normal variables, the mean is the subtraction of the means, while the standard deviation is the square root of the sum of the variances.

A consumer group has determined that the distribution of life spans for gas ranges (stoves) has a mean of 15.0 years and a standard deviation of 4.2 years. Sample of 35:

This means that:

[tex]\mu_G = 15[/tex]

[tex]s_G = \frac{4.2}{\sqrt{35}} = 0.71[/tex]

The distribution of life spans for electric ranges has a mean of 13.4 years and a standard deviation of 3.7 years. Sample of 40:

This means that:

[tex]\mu_E = 13.4[/tex]

[tex]s_E = \frac{3.7}{\sqrt{40}} = 0.585[/tex]

Which of the following best describes the sampling distribution of the difference in mean life span of gas ranges and electric ranges?

Shape is approximately normal.

Mean:

[tex]\mu = \mu_G - \mu_E = 15 - 13.4 = 1.6[/tex]

Standard deviation:

[tex]s = \sqrt{s_G^2+s_E^2} = \sqrt{0.71^2+0.585^2} = 0.92[/tex]

So the correct answer is given by option b.


Related Questions

Q2) A

farmer distributed an amount of Rs 56 among his two children in the ratio 3 :5 How much amount was received by each of them

Answers

[tex]\huge\mathfrak\purple{answer}[/tex]

[tex]3x + 5x= \red{56} \\ 8x = \red{56} \\ x = \frac{56}{8} \\ x= \red{7}[/tex]

(Mark me brainliest if you're satisfied with the answer :))

Solve the system using elimination.
3x + 5y = -2
-x + 2y = 8
([?], [ ]

Answers

Answer:

Step-by-step explanation:

To eliminate the x terms, first multiply the second equation by 3:

-3x + 6y = 24

then add it to the first equation:

3x + 5y = -2

-3x + 6y = 24

------------------

0x + 11y = 22

y = 2

plug the value of y into one of the equations:

-x + 2(2) = 8

x = 4-8 = -4

(x,y) = (-4, 2)

Can someone pls help me I’ll mark brainiest

Answers

Answer:

70%

Step-by-step explanation:

Because 100% - 30% = 70%

6+x=23 what is x in the equation

Answers

the correct answer is x=17

i need help with everything please if you help you are a legend please.

Answers

2. Closer to 0. Because it is always getting smaller. The smaller it gets, the closer it get to 0.

3.

a. Closest to 1.

b. Closest to 0.

c. (1/12)

4.

a. Closest to 1.

b. Closest to (1/2)

c. (14/16)-(10/16)=(4/16)

What is the median of data set 32 25 25 32 32 10 -10 25 ​

Answers

Answer:

-10, 10, 25, 25, 25, 32, 32, 32

Its 25

Step-by-step explanation:

The median is the middle number if there are an even amount of numbers you would have two medians add them the divide by two

the median is 25. you can put the numbers in order from least to greatest values and cross out one by one to make it easier! hope this helps :D

-2y + 4 > 10

solve the inequality

Answers

Step-by-step explanation:

-2y+4>10

subtract 4 from both sides

-2y+4-4>10-4

-2y>6

divide both sides by two

-2/2y>6/2

-1y>3

if negative y is greater than three than you have to multiply both sides of the equation by -1

y>-3 if you put that back into the earlier equation it is impossible.

so we have to switch the signs to < or less than

y<-3

Hope that helps:)

more on fraction

21×5​

Answers

Answer:

105.

Step-by-step explanation:

21+21+21+21+21=105.

the picture is the question​

Answers

Answer:

Swap the direction of the inequality

Step-by-step explanation:

Anytime you multiply or divide by a negative number in an inequality, you flip the symbol so > turns into <

How many quarts are in two gallons?

Answers

2 gallons = 8 quarts

hope it's help ;3

I need some help
I will give you brainliest and heart!

Answers

Answer:

Correct!

Step-by-step explanation:

First, I'll try to solve it myself.

2(2a-1)+3a=7a-2

7a-2

4a-2=7a-2

His is very correct!

Miss logan leaves school at 15:55 it takes her 1 hour and 20 mins to get home what time does she arrive home? answer using 24 hour time​

Answers

Answer:

5:15

Step-by-step explanation:

15:55 = 3:55 in normal time

3:55 + 1 hr = 4:55

4:55 + 20 min = 5:15

A student must leave for campus in 10 minutes or he will be late for class.​ Unfortunately, he is snowed in. He can shovel the driveway in 18 ​minutes, and his brother claims to be able to do it in 12 minutes. If they shovel​ together, how long will it take to clear the​ driveway? Will this give enough time for the student to get to the​ campus?

Answers

Answer:

I believe if they did it together they would finish in 6 minutes

Step-by-step explanation:

Does anyone know the answer??????

Answers

Answer:

i think its the 2nd choice but im not 100% sure

I NEED HELP WORTH THIS there is one more option of 6,6 also

Answers

Answer:

C. (2,4)

Step-by-step explanation:

Please this will determine if I pass

Answers

The answer is B through ASA (Angle-Side-Angle) similarity criterion.

Pythagorean theorem

Answers

Answer:

a^2 + b^2 = c^2

Step-by-step explanation:

Answer:

a^2 + b^2 = c^2

Step-by-step explanation:

Used to find side lengths of right triangles, a and b represent sides, while c represents the hypotenuse.

Plss I need help

ASAP

Answers

Answer:

21x+56 %thats ur answer hope it worked !

Answer:

21x

Step-by-step explanation:

ssjsjsjsjsjsssjsjsss

Simplify the expression: 5(-5 + 2y) =

Answers

The answer is-25+ 10y

Determine the length of the diagonals of the isosceles trapezoid below when KL= h+7 and UE= 4h-25

Answers

Answer:

KL= 17.67 unit

UE = 17.67 unit

Step-by-step explanation:

Given:

Diagonals

KL= h+7

UE = 4h-25

Find:

Length of diagonals KL and UE

Computation:

We know that in isosceles trapezoid the length of diagonals are equal

So,

KL = UE

h+7 = 4h-25

3h = 32

h = 10.67

So,

KL= h+7

KL= 10.67+7

KL= 17.67 unit

UE = 4h-25

UE = 4(10.67)-25

UE = 17.67 unit

Pls answer this for me​

Answers

Answer:

A) 216in squared

Step-by-step explanation:

6 / 2 = 3

4 * 3 = 12

12 * 2 = 24

5 * 12 = 60

60 * 2 = 120

6 * 12 = 72

24 + 72 + 120 = 216in^2

Hope this helped! Have a nice day! Plz mark as brainliest!!! :D

-XxDeathshotxX

The equation x = 1 is an example of linear but not function. Why?

Answers

Because there is more than two y values for x = 1

Answer these two correctly and I’ll reward 8 points + brainalist

Answers

Answer:

1. B.

2. C.

Step-by-step explanation:

1. It only has one cell so it needs to rely on other organisms in order for it to survive

2. Chloroplasts are only found in plants you can remember it by "Chloroplants"

The Gable Construction Corporation has placed bids for installing electronic message boards on two different highways.
Because of competition from other companies, Gable Construction Corporation officials estimate that the probability that
they will be awarded the Macon Expressway contract is 0.65 and the probability that they will be awarded the Seaview
Expressway contract is 0.43. Furthermore, the probability that they will be awarded both contracts is 0.22. What is the
probability that they will be awarded the contract for either the Macon Expressway or the Seaview Expressway

Answers

Answer:

0.64 = 64% probability that they will be awarded the contract for either the Macon Expressway or the Seaview Expressway

Step-by-step explanation:

We solve this question using these events as Venn sets.

I am going to say that:

Event A: Awarded the Macon Expressway.

Event B: Awarded the Seaview Expressway.

Probability that they will be awarded the Macon Expressway contract is 0.65

This means that [tex]P(A) = 0.65[/tex]

The probability that they will be awarded the Seaview Expressway contract is 0.43.

This means that [tex]P(B) = 0.43[/tex]

Furthermore, the probability that they will be awarded both contracts is 0.22.

This means that [tex]P(A \cap B) = 0.22[/tex]

What is the

Probability that they will be awarded the contract for either the Macon Expressway or the Seaview Expressway?

Only A:

[tex]P(A) - P(A \cap B) = 0.65 - 0.22 = 0.43[/tex]

Only B:

[tex]P(B) - P(A \cap B) = 0.43 - 0.22 = 0.21[/tex]

Either

0.43 + 0.21 = 0.64

0.64 = 64% probability that they will be awarded the contract for either the Macon Expressway or the Seaview Expressway

calculate the GPA of a student with the following grades: B (3 hours), D (8 hours), C (18 hours). Note that an A is equivalent to 4.0, a B is equivalent to a 3.0, a C is equivalent to a 2.0, a D is equivalent to a 1.0, and an F is equivalent to a 0. Round your answer to two decimal places.

Answers

Answer:

The GPA of the student is 1.83.

Step-by-step explanation:

We use a weighted average to solve this question.

We have the following grades:

B, which is equivalent to 3, with weight 3.

D, which is equivalent to 1, with weight 8.

C, which is equivalent to 2, with weight 18.

So

[tex]M = \frac{3*3 + 1*8 + 2*18}{3 + 8 + 18} = \frac{53}{29} = 1.83[/tex]

The GPA of the student is 1.83.

Pierre found a new store where he hopes to save
money on his supplies. He bought 4 brushes and 7
tubes of paint for $32. He has another order for 6
brushes and 8 tubes of paint that will cost $43.
What is the cost of one brush? What is the cost of
one tube of paint?

Answers

Your first equation is 4x + 7y= 32, the x’s representing the brushes and the y’s the tubes of paint. Our second equation is 6x+8y=43. What I did is I multiplied the first equation by 1.5 so that it turns into 6x+10.5y=48. Then I subtracted the second equation from the first, canceling out the x’s and leaving us with 2.5y=5. Then divided and got y=2. We then go back to any of the original equations and plug it in to get the x’s.
6x+8(2)=43. We get 6x+16=43. We subtract and are left with 6x=27 and then x=4.5. Then plug both of them in to a different equation to double check. You could also use substitution by isolating one of the variables in one equation and then plugging it in to the other one.

100 - 50 + 4

HELP PLS PLS PLSSSSS

Answers

Answer:

54

Step-by-step explanation:

100-50+4=50+4

=54

.....


Jimmy ate 1/3 of his sandwich at lunch. He ate another 2/3 of the sandwich. How much of the sandwich did Jimmy eat in all?
A.1/3
B.2/3
C.3/3
D.5/3

Answers

The answer is c (this needs too be 20 characters long)

which is the least -1 1/4 or -3/2

Answers

Answer:

-3/2

Step-by-step explanation:

Can someone write down the answers pls!!!!!!!!!!

Answers

Step-by-step explanation:

6b x>=1

6c y>7

7a x>3

7b -2<=2x<6

-1<=x<3

answer:-1,0,1,2,3

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