A bag contains 7 red, 4 blue, and 6 white marbles.

Please help asap im super confused<br> Which is the equation for BC?

Aloiza [94]

Points on BC:
(-5, 5) and (0,1)
Slope = (5-1)/(-5-0)
Slope = -4/5

y = mx + c
y = -4/5x + c

at point (0,1)
1 = -4/5(0) + c
c = 1

y = -4/5x + 1
5y = -4x + 5
4x + 5y = 5 (Answer D)

6 0

3 years ago

The mean time required to repair breakdowns of a certain copying machine is 93 minutes. The company which manufactures the machi

Sonja [21]

Answer:

$t=\frac{88.8-93}{\frac{26.6}{\sqrt{73}}}=-1.349$

$p_v =P(t_{(72)}$

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to fail reject the null hypothesis, and we can't concluce that the true mean is less than 93 min at 5% of signficance.

Step-by-step explanation:

Data given and notation

$\bar X=88.8$ represent the sample mean

$s=26.6$ represent the sample standard deviation for the sample

$n=73$ sample size

$\mu_o =93$ represent the value that we want to test

$\alpha=0.05$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean i lower than 93 min, the system of hypothesis would be:

Null hypothesis: $\mu \geq 93$

Alternative hypothesis: $\mu < 93$

If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{88.8-93}{\frac{26.6}{\sqrt{73}}}=-1.349$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=73-1=72$

Since is a one side test the p value would be:

$p_v =P(t_{(72)}$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to fail reject the null hypothesis, and we can't concluce that the true mean is less than 93 min at 5% of signficance.

5 0

2 years ago

"Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given st

11111nata11111 [884]

Answer:

The error E = ± 4.04 %

Step-by-step explanation:

Solution:-

- The sample data is used to estimate the population proportion ( p ).

- The success p^ = success percentage = 40 %

- The confidence interval CI = 98%

- The sample size n = 800

- The margin of error E:

- The margin of error "E" for estimation of population proportion ( p ) is given by:

$E = z-critical*\sqrt{\frac{p~ ( 1 - p~ )}{n} }$

Where, Z-critical value is defined by the significance level:

P ( Z < Z-critical ) = α / 2

Where, α : Significance level

α = 1 - CI

P ( Z < Z-critical ) = (1 - 0.98) / 2

P ( Z < Z-critical ) = 0.01

Z-critical = 2.33

- The error E of estimation is:

$E = 2.33*\sqrt{\frac{0.4 ( 1 - 0.4 )}{800} }\\\\E = 0.04035$

- The error E = ± 4.04 %

6 0

2 years ago

On a farm there are three-legged-cows and chickens. There are total of 127 heads and 353 legs. How many three-legged-cows are on

olga nikolaevna [1]

Answer: There are 99 three-legged-cows and 28 chickens.

Step-by-step explanation:

Let x be the number of three-legged-cows and y be the number of chickens.

Number of legs in chicken = 2

The according to the question, we have the following equations :-

$\text{For heads }x+y=127------(1)\\\\\text{For legs }3x+2y=353------(2)$

Multiplying 2 to the equation (1), we get

$2x+2y=254--------(3)$

Now, subtract equation (3) from (2), we get

$x=353-254=99$

Put x= 99 in (1), we get

$99+y=127\\\\\Rightarrow\ y=127-99=28$

Hence, there are 99 three-legged-cows and 28 chickens.

6 0

3 years ago

The strength of paper used in the manufacturing of cardboard boxes (y) is related to percentage of hardwood concentration in the

Elena-2011 [213]

Answer:

At a significance level of 0.05, there is enough evidence to claim that there is a significant relationship between x and y.

P-value = 0.003.

Step-by-step explanation:

If we perform a regression analysis relating x and y, we get the best fitting line with equation:

$y=15.82x+92.9$

and a correlation coefficient r:

$r=0.693$

We have to test the hypothesis, where the alternative hypothesis claims that there is a relationship between these two variables, and the null hypothesis claiming there is no relationship (meaning that the correlation is not significantly different from 0).

This can be written as:

$H_0: \rho=0\\\\H_a:\rho\neq0$

where ρ is the population correlation coefficient for x and y.

The significance level is assumed to be 0.05.

The sample size is n=16.

The degrees of freedom are df=14.

$df=n-2=16-2=14$

The test statistic can be calculated as:

$t=\dfrac{r\sqrt{n-2}}{\sqrt{1-r^2}}=\dfrac{0.693\sqrt{14}}{\sqrt{1-(0.693)^2}}=\dfrac{2.593}{0.721}=3.597$

For a test statistic t=2.05 and 14 degrees of freedom, the P-value is calculated as:

$\text{P-value}=2\cdot P(t>3.597)=0.003$

The P-value (0.003) is smaller than the significance level (0.05), so the effect is significant enough.

The null hypothesis is rejected.

At a significance level of 0.05, there is enough evidence to claim that there is a significant relationship between x and y.

3 0

2 years ago