Please everyone, I need help with this question and it's worth 10 good points.

A consumer group has determined that the distribution of life spans for gas ranges (stoves) has a mean of 15.0 years and a stand

Art [367]

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 $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

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:

$\mu_G = 15$

$s_G = \frac{4.2}{\sqrt{35}} = 0.71$

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:

$\mu_E = 13.4$

$s_E = \frac{3.7}{\sqrt{40}} = 0.585$

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:

$\mu = \mu_G - \mu_E = 15 - 13.4 = 1.6$

Standard deviation:

$s = \sqrt{s_G^2+s_E^2} = \sqrt{0.71^2+0.585^2} = 0.92$

So the correct answer is given by option b.

8 0

3 years ago

The answer too the question the Unite rate

Olin [163]

A unit rate is a rate with 1 in the denominator. If you have a rate, such as price per some number of items, and the quantity in the denominator is not 1, you can calculate unit rate or price per unit by completing the division operation: numerator divided by denominator.

6 0

2 years ago

Alvin wants to know what his average paddling rate was for a canoe trip to a campsite. On the way there it took him 8 hours agai

Marizza181 [45]

let

r--------> Alvin's average paddling rate in km/hour

y -------> speed of the current in km/hour

we know that

speed= distance/time ------> solve for distance

distance=speed*time

to Campsite against the current

speed=r-y-----> speed=(r-3)

time=8 hours

distance=(r-3)*8------> equation 2

From Campsite with the current

speed=r+y-----> speed=(r+3)

time=3 hours

distance=(r+3)*3------> equation 1

equate equation 1 and equation 2-----> because is the same distance

(r+3)*3=(r-3)*8----> 3r+9=8r-24----> 8r-3r=24+9-----> 5r=33----> r=6.6 km/hour

therefore

the answer is

Alvin's average paddling rate is 6.6 km/hour

7 0

3 years ago

Find angle FEG<br> A. 20<br> B. 40<br> C 60<br> D. 120

Nana76 [90]

<GED=180-x-40

x+2x+180-x-40=180

2x=40

x=20

<GEF=20+40=60¤

Answer: C

4 0

2 years ago

Read 2 more answers

A recipe requires 7/8 stick of butter for each 1 1/4 cups of flour. Find the unit rate of sticks of butter to cups of flour.

Sholpan [36]

Answer:

Let R = unit rate

R = (7/8) ÷ 1_1/4

R = (7/8) ÷ (5/4)

R = (7/8) • (4/5)

R = (7/2) • (1/5)

R = 7/10

Step-by-step explanation:

4 0

2 years ago