Hi! Okay so I need someone to solve these 2 please! Ty! I will give brainliest!!! :))

Please Help me!!! <br><br><br> I know the answer but I don’t understand how to get that answer

worty [1.4K]

-7 ÷ 2 1/2
Okay, so first, put the -7 over one and make 2 1/2 an improper fraction. so now:
-7/1 ÷ 5/2
Then, take the reciprocal of 5/2 and multiply it by -7/1
-7/1 × 5/2
Which would be -35/2

5 0

3 years ago

Can you please help me get this done it’s due TOMORROW!

siniylev [52]

Answer:

Hi , the answer is 280-140/ 4-2 = 140/2

y = 2/140 x

b . 70 beats each minute

Step-by-step explanation:

we will take a 2 point from the graph

(280,4) , (y1,x1) and (140, 2) , (y2,x2) each point represent a (y,x) point

m = y1-y2 / x1-x2 = 280-140 / 4-2 = 140 /2

now , y/x = 140/2 ... by B. Multiplication we will get y = 2/140 x

b .

from the graph we see that every minute the curve increase 70 beats

Thanks

8 0

2 years ago

8. Jack is going to paint the ceiling and four

Ugo [173]

Answer:

D

Step-by-step explanation:

7 0

2 years ago

A red candle is 8 inches tall and burns at a rate of 7/10 inch per hour. a blue cans is 6 inches tall and burns at a rate of 1/5

Galina-37 [17]

Let t = number of hours

The first candle starts at 8 inches.
It burns at 7/10 inch per hour, so in t hours it burns (7/10)t inches.
After t hours, its length is 8 - (7/10)t

The second candle starts at 6 inches.
It burns at 1/5 inch per hour, so in t hours it burns (1/5)t inches.
After t hours, its length is 6 - (1/5)t

You want the lengths to be equal, so the equation is

8 - (7/10)t = 6 - (1/5)t

4 0

3 years ago

Let n1equals50, Upper X 1equals30, n2equals50, and Upper X 2equals10. Complete parts (a) and (b) below. a. At the 0.05 leve

Viefleur [7K]

Answer:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

$z=\frac{0.6-0.2}{\sqrt{0.4(1-0.4)(\frac{1}{50}+\frac{1}{50})}}=4.082$

$p_v =2*P(Z>4.082)=4.46x10^{-5}$

So the p value is a very low value and using any significance level for example $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say the the proportion 1 is significantly different from proportion 2.

Step-by-step explanation:

1) Data given and notation

$X_{1}=30$ represent the number of people with a characteristic in 1

$X_{2}=10$ represent the number of people with a characteristic in 2

$n_{1}=50$ sample of 1 selected

$n_{2}=50$ sample of 2 selected

$p_{1}=\frac{30}{50}=0.6$ represent the proportion of people with a characteristic in 1

$p_{2}=\frac{10}{50}=0.2$ represent the proportion of people with a characteristic in 2

z would represent the statistic (variable of interest)

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

2) Concepts and formulas to use

We need to conduct a hypothesis in order to check if the proportion 1 is different from proportion 2 , the system of hypothesis would be:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

We need to apply a z test to compare proportions, and the statistic is given by:

$z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}$ (1)

Where $\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{30+10}{50+50}=0.4$

3) Calculate the statistic

Replacing in formula (1) the values obtained we got this:

$z=\frac{0.6-0.2}{\sqrt{0.4(1-0.4)(\frac{1}{50}+\frac{1}{50})}}=4.082$

4) Statistical decision

For this case we don't have a significance level provided $\alpha$ , but we can calculate the p value for this test.

Since is a two sided test the p value would be:

$p_v =2*P(Z>4.082)=4.46x10^{-5}$

So the p value is a very low value and using any significance level for example $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say the the proportion 1 is significantly different from proportion 2.

3 0

3 years ago