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3 years ago

Solve this expression 4i-√-100

Mathematics

1 answer:

saul85 [17]3 years ago

7 0

Answer:
Undefined
Explanation:
The square root of a negative number does not exist in the set of real numbers

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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

Please help thank you!

Arte-miy333 [17]

Answer:

golf: $10
batting: $2.50

Step-by-step explanation:

We can write two equations in the two unknowns using the given relations. Let g and b represent the costs of a round of golf and a turn in the batting cage, respectively.

5g +4b = 60 . . . . . Sylvester's expense

3g +6b = 45 . . . . . Lin's expense

Dividing the second equation by 3 gives ...

g +2b = 15 ⇒ 2b = 15 -g

Substituting into the first equation, we have ...

5g +2(2b) = 60

5g +2(15 -g) = 60 . . . . . substitute for 2b

3g = 30 . . . . . . . . . subtract 30, collect terms

g = 10 . . . . . . . divide by 3

2b = 15 -10 = 5 . . . . use the value of g to find b

b = 2.5 . . . . . . . . divide by 2

Mini golf costs $10 per round; batting cages cost $2.50 per turn.

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Answer:

got to settings

Step-by-step explanation:

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Hi help me please, I can't seem to figure this one out

Nastasia [14]

Answer:

x= 2.73cm

For the same angle we just work out 1cm first.

a^2+ b^2= c^2

0.82^2 + b^2 = 1^2 = changing to units 10

6.724 + b^2 = 10

10-6.724 = 2.276

Then x 3 and change units down by 10= 0.6828

Step-by-step explanation:

Below shows why we must convert to mm from cm

a^2+ b^2= c^2

0.82^2 + b^2 = 1^2 =

0.6724 + b^2 = 1

1 - 0.6724 = b = 0.2276

0.2276 x 3 = 0.6828 cm

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