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3 years ago

1.

1 answer:

3 0

The commutative property of addition means the order of the addends doesn't matter; we get the same sum. In symbols

$a+b = b+a$

11 + 7 = 7 + 11, choice B, is a good illustration of commutativity.

The next part asks us to use the commutative property. Looking at the choices, we see it's not the commutative property of addition we're to use, it's the commutative property of multiplication. Let's write that generally first:

 $ab = ba$

Applying that, (4 + 7) * 3 = 3*(4+7), again choice B.

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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

Identify the oblique asymptote of f(x) = 2x^2+3x+8/x+3

Lostsunrise [7]

Answer:

Step-by-step explanation:

7vito6u

7 0

3 years ago

Read 2 more answers

Find all the solutions of sin x + cos x = 1 in the interval [0, 2pie).

Mashcka [7]

Answer:

X = 0, π/2 in the interval [0, 2pi).

Step-by-step explanation:

Use the auxiliary angle method:

R sin(x + a) = Rsin x cos a + Rcos x sin a = 1

sin x + cos x = 1

Comparing coefficients:

R cos a = 1 and R sin a = 1, so

tan a = R sin a / R cos a = 1

So a = π/4 radians.

Also R^2(sin^2 a + cos^2 a) = 1^2 + 1^2 = 2

Therefore R = √2.

So √2 sin (x +π/4 = 1

sin x + π/4 = 1/√2

x + π/4 = π/4

x = 0 radians

Also

x = 0 + π/2 = π/2.

8 0

3 years ago

{f(1)=15 f(n)=f(n-1)•n

zheka24 [161]

I solved the second equation and it’s zero, I’m not really sure how to help with the top on tho. I am really sorry :/

5 0

3 years ago

Read 2 more answers

Im. lost plese help I suck at Unit Rates

Makovka662 [10]

Luke: 2 miles in 40 minutes, 20 minutes a mile, (2/40 = 20 minutes a mile)
Luke's speed is 3 miles an hour (60minutes/20minutes a mile = 3miles).

Sally: 0.05 miles a minute, 60 minutes in an hour, 60 x 0.05 = 3 miles an hour. Or 0.05 miles a minute, 40 minutes walked, 40 x 0.05 = 2 miles walked.

There are a few other ways to show that they are accurate rates.

So yes, they are both correct rates.

7 0

3 years ago