Ask question

Ask question

All categories

3 years ago

11

HURRY! Roberto concluded that 8th graders are more likely than 9th graders to have a summer job because more 8th graders than 9t

h graders responded that they have a summer job. Is Roberto correct? Explain why or why not

1 answer:

leva [86]3 years ago

4 0

Answer :What words or phrases did the author use to express his opinion about city gardening?

Step-by-step explanation:

You might be interested in

The ratio of a number and 18 is equal to the difference of a number squared and 5

boyakko [2]

Answer:

The number is 2.26

Step-by-step explanation:

Let The given numbers be x

Now according to question :

x : 18 = x² - 5

I.e x = 18 × ( x² - 5 )

or, x = 18 × x² - 90

or, 18 x² - x - 90 = 0

Or, From quadratic equation , the value of x

x = $\frac{-b\pm \sqrt{b^{2}-4\times a\times c}}{2\times a}$

Or, x = $\frac{+\pm \sqrt{-1^{2}-4\times 18\times -90}}{2\times 18}$

Or, x = $\frac{1\pm \sqrt{6481}}{36}$

So, x = $\frac{1\pm 80.50}{36}$

∴ x = $\frac{81.50}{36}$ = 2.26

Hence The number is 2.26 Answer

8 0

3 years ago

By definition pH = - log H+], where H*] is the hydrogen concentration in $ ltext(moles per liter]$. If the pH

Ivanshal [37]

A ........................ig

5 0

3 years ago

For what value of k, the zeroes of x2 + kx + 12 will differ by 1?

asambeis [7]

Let <em>a</em> and <em>b</em> be the zeroes of <em>x</em>² + <em>kx</em> + 12 such that |<em>a</em> - <em>b</em>| = 1.

By the factor theorem, we can write the quadratic in terms of its zeroes as

<em>x</em>² + <em>kx</em> + 12 = (<em>x</em> - <em>a</em>) (<em>x</em> - <em>b</em>)

Expand the right side and equate the coefficients:

<em>x</em>² + <em>kx</em> + 12 = <em>x</em>² - (<em>a</em> + <em>b</em>) <em>x</em> + <em>ab</em>

Then

<em>a</em> + <em>b</em> = -<em>k</em>

<em>ab</em> = 12

The condition that |<em>a</em> - <em>b</em>| = 1 has two cases, so without loss of generality assume <em>a</em> > <em>b</em>, so that |<em>a</em> - <em>b</em>| = <em>a</em> - <em>b</em>.

Then if <em>a</em> - <em>b</em> = 1, we get <em>b</em> = <em>a</em> - 1. Substitute this into the equations above and solve for <em>k</em> :

<em>a</em> + (<em>a</em> - 1) = -<em>k</em> → 2<em>a</em> = 1 - <em>k</em> → <em>a</em> = (1 - <em>k</em>)/2

<em>a</em> (<em>a</em> - 1) = 12 → (1 - <em>k</em>)/2 • ((1 - <em>k</em>)/2 - 1) = 12

→ (1 - <em>k</em>)²/4 - (1 - <em>k</em>)/2 = 12

→ (1 - <em>k</em>)² - 2 (1 - <em>k</em>) = 48

→ (1 - 2<em>k</em> + <em>k</em>²) - 2 (1 - <em>k</em>) = 48

→ <em>k</em>² - 1 = 48

→ <em>k</em>² = 49

→ <em>k</em> = ± √(49) = ±7

8 0

3 years ago

HELP ASAP, PLEASE!!!!

GalinKa [24]

Using the t-distribution, as we have the standard deviation for the sample, we have that the test statistic is given by:

$t = \frac{-20 - 0}{\sqrt{\frac{32.66}{7}}}$

<h3>What are the hypothesis tested?</h3>

At the null hypothesis, it is tested if there is no difference, that is:

$H_0: \mu = 0$

At the alternative hypothesis, it is tested if there is a difference, that is:

$H_1: \mu \neq 0$

<h3>What is the test statistic?</h3>

The test statistic is given by:

$t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}$

The parameters are:

$\overline{x}$ is the sample mean.

$\mu$ is the value tested at the null hypothesis.

s is the standard deviation of the sample.

n is the sample size.

In this problem, $\mu = 0$ is tested at the null hypothesis, and the sample is: 20, -40, -40, 0, 20, - 60, -40, hence:

$\overline{x} = -20, s = \sqrt{32.66}, n = 7$ .

Hence, the test statistic is:

$t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}$

$t = \frac{-20 - 0}{\frac{\sqrt{32.66}}{\sqrt{7}}}$

$t = \frac{-20 - 0}{\sqrt{\frac{32.66}{7}}}$

More can be learned about the t-distribution at brainly.com/question/16313918

5 0

3 years ago

Help please.............

Aleksandr [31]

Answer:

10 C

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers