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nikitadnepr [17]
3 years ago
8

Plzzz answerrrrrrrrrrr

Mathematics
2 answers:
skelet666 [1.2K]3 years ago
5 0
9. -16
10. 3
11. 4
12. -5
14. -12
15. 20
frutty [35]3 years ago
3 0

Answer:

9. -16

10. 3

11. 4

Step-by-step explanation:

9. 21 = 5 - r

Subtract 5 from both sides;

16 = -r

Divide both sides by -1

-16 = r OR r = -16

10. 8 - 5b = -7

Subtract 8 from both sides;

-5b = -15

Divide both sides by -5

b = 3

11. -10 = 6 - 4m

Subtract 6 from both sides;

-16 = -4m

Divide both sides by -4

4 = m OR m = 4

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A sample of 12 radon detectors of a certain type was selected, and each was exposed to 100 pCI/L of radon. The resulting reading
valkas [14]

Answer:

Null hypothesis:\mu = 100  

Alternative hypothesis:\mu \neq 100  

t=\frac{98.375-100}{\frac{6.109}{\sqrt{12}}}=-0.921  

p_v =2*P(t_{11}  

Step-by-step explanation:

1) Data given and notation  

Data: 105.6, 90.9, 91.2, 96.9, 96.5, 91.3, 100.1, 105.0, 99.6, 107.7, 103.3, 92.4

We can calculate the sample mean and deviation for this data with the following formulas:

\bar X =\frac{\sum_{i=1}^n X_i}{n}

s=\sqrt{\frac{\sum_{i=1}^n (X_i- \bar X)^2}{n-1}}

The results obtained are:

\bar X=98.375 represent the sample mean  

s=0.6.109 represent the sample standard deviation  

n=12 sample size  

\mu_o =100 represent the value that we want to test  

\alpha represent the significance level for the hypothesis test.  

z would represent the statistic (variable of interest)  

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

2) State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the mean is equal to 100pCL/L, the system of hypothesis are :  

Null hypothesis:\mu = 100  

Alternative hypothesis:\mu \neq 100  

Since we don't know the population deviation, 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".  

3) Calculate the statistic  

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

t=\frac{98.375-100}{\frac{6.109}{\sqrt{12}}}=-0.921  

4) P-value  

First we need to find the degrees of freedom for the statistic given by:

df=n-1=12-1=11

Since is a two sided test the p value would given by:  

p_v =2*P(t_{11}  

5) Conclusion  

If we compare the p value and the significance level assumed \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, so we can conclude that the true mean is not significant different from 100 at 5% of significance.  

3 0
3 years ago
5231+4331=9562 3696+6939
7nadin3 [17]

Answer:

10635

Step-by-step explanation:

Honestly, I dunno. I just added it.

5 0
3 years ago
Read 2 more answers
3. What are the domain and range of (x) = 4* ?<br> Domain: <br><br> Range:
Natali [406]
I think you can do that on photo math
6 0
2 years ago
a dolphin is swimming 18 feet below the surface of the ocean. there is a coast guard helicopter 75.5 feet above the surface of t
Sever21 [200]

Answer:

93.5

Step-by-step explanation:

I think because u would take -18 -18 + 75.5.

can I have brainlist please.

6 0
2 years ago
45% of 40 is 18% of what number?
alexandr1967 [171]
So 45% OF 40 is 
45% * 40 
0.45 * 40
that is 18

18 is 18% of what number?
18 = 18% * x
18 = 0.18 * x
divide both sides by 0.18
100 = x
45 % of 40, which is 18, and is 18% of 100.

Hope this helps
3 0
3 years ago
Read 2 more answers
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