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3 years ago

Solve for x: −2x + 5 < 7 x > −1 x < −1 x > −6 x < −6

Mathematics

2 answers:

docker41 [41]3 years ago

4 0

-2x + 5 < 7
-5 -5
-2x < 2
/-2 /-2
x > -1
When multiplying or dividing by a negative number, flip the inequality.

Art [367]3 years ago

3 0

I believe the answer is x>-1

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The U.S. Center for Disease Control reports that the mean life expectancy was 47.6 years for whites born in 1900 and 33.0 years

inn [45]

Answer:

b. The null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0$

c. Student's t distribution, as it is a two-sample test for the difference between means.

d. Test statistic t = 5.42.

P-value = 0

e. They appear to be significantly different, as the sample data gives strong evidence that the difference is greater than 0.

Step-by-step explanation:

This is a hypothesis test for the difference between populations means.

The claim is that the mean life spans in the county is significantly different for whites and nonwhites.

Then, the null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2\neq 0$

The significance level is 0.05.

The sample 1 (white), of size n1=124 has a mean of 45.3 and a standard deviation of 12.7.

The sample 2 (non-white), of size n2=82 has a mean of 34.1 and a standard deviation of 15.6.

The difference between sample means is Md=11.2.

$M_d=M_1-M_2=45.3-34.1=11.2$

The estimated standard error of the difference between means is computed using the formula:

$s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{12.7^2}{124}+\dfrac{15.6^2}{82}}\\\\\\s_{M_d}=\sqrt{1.301+2.968}=\sqrt{4.269}=2.066$

Then, we can calculate the t-statistic as:

$t=\dfrac{M_d-(\mu_1-\mu_2)}{s_{M_d}}=\dfrac{11.2-0}{2.066}=\dfrac{11.2}{2.066}=5.42$

The degrees of freedom for this test are:

df=n_1+n_2-2=124+82-2=204

This test is a two-tailed test, with 204 degrees of freedom and t=5.42, so the P-value for this test is calculated as (using a t-table):

$\text{P-value}=2\cdot P(t>5.42)=0.0000002$

As the P-value (0.0000002) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the mean life spans in the county is significantly different for whites and nonwhites.

4 0

3 years ago

83/10y-(38/11-11/4y)

IrinaK [193]

Answer:

I think 83 ÷ 10 and it said that it incorrect

Step-by-step explanation:

5 0

3 years ago

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Find the missing side . round the the nearest tenth

lys-0071 [83]

$S\frac{O}{H} C\frac{A}{H} T\frac{O}{A}$

$Sin=\frac{Opposite}{Hypotenuse} Cos=\frac{Adjacent}{Hypotenuse} Tan=\frac{Opposite}{Adjacent}$

7) You have the opposite. You need the adjacent.

$Tan=\frac{Opposite}{Adjacent}$

$Tan57=\frac{12}{x}$

$x=\frac{12}{Tan57}$

x = 7.79289... =

8) You have the hypotenuse. You need the Opposite.

$Sin=\frac{x}{Hypotenuse}$

$Sin37=\frac{x}{13}$

x = sin37 × 13

x = 7.8235... =

9) You have the hypotenuse. You need the opposite.

$Sin=\frac{x}{Hypotenuse}$

$Sin59=\frac{x}{11}$

x = sin59 × 11

x = 9.4288.... =

10) You have the hypotenuse. You need the opposite.

$Sin=\frac{x}{Hypotenuse}$

$Sin53=\frac{x}{11}$

x = sin53 × 11

x = 8.7459.... =

7 0

3 years ago

Student performance across discussion sections: A professor who teaches a large introductory statistics class (197 students) wit

adell [148]

Answer:

The test is not significant at 5% level of significance, hence we conclude that there's no variation among the discussion sections.

Step-by-step explanation:

Assumptions:

1. The sampling from the different discussion sections was independent and random.

2. The populations are normal with means and constant variance

$H_0:$ There's no variation among the discussion sections

$H_1:$ There's variation among the discussion sections

$\alpha =0.05$

Df Sum Sq Mean sq F value Pr(>F)

Section 7 525.01 75 1.87 0.99986

Residuals 189 7584.11 40.13

Test Statistic = $F= \frac{75}{40.13} =1.87$

$Pr(>F) = 0.99986$

Since our p-value is greater than our level of significance (0.05), we do not reject the null hypothesis and conclude that there's no significant variation among the eight discussion sections.

3 0

3 years ago

Help me plz I don't get it !!!!!!!!

Alona [7]

Answer: B.

It grows 3 inches per week

3 0

3 years ago

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