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elena-14-01-66 [18.8K]
3 years ago
12

What’s 3.8 - (-7.45)

Mathematics
1 answer:
Varvara68 [4.7K]3 years ago
6 0

it is 11.25................................

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The mean age when smokers first start is 13 years old with a population standard deviation of 2 years. A researcher thinks that
lakkis [162]

Answer:

Null hypothesis:\mu = 13  

Alternative hypothesis:\mu \neq 13

z=\frac{12.2-13}{\frac{2}{\sqrt{30}}}=-2.191  

a. Reject the null hypothesis

c. There is enough evidence to support the claim

Step-by-step explanation:

Data given and notation  

\bar X=12/2 represent the sample mean  

s=20000 represent the standard deviation for the sample  

\sigma =2 represent the population standard deviation

n=30 sample size  

\mu_o =13 represent the value that we want to test  

\alpha=0.05 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)  

State the null and alternative hypotheses to be tested  

We need to conduct a hypothesis in order to determine if the smoking age has significantly changed since the invention of ENDS—electronic nicotine delivery systems, the system of hypothesis would be:  

Null hypothesis:\mu = 13  

Alternative hypothesis:\mu \neq 13

Compute the test statistic

We know the population deviation, so for this case is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:  

z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}} (1)  

z-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".  

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

z=\frac{12.2-13}{\frac{2}{\sqrt{30}}}=-2.191  

What do you conclude? Using the p-value approach  

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

p_v =2*P(Z  

Since the p_v then the correct decision is:

a. Reject the null hypothesis

And the best conclusion is :

c. There is enough evidence to support the claim

6 0
3 years ago
Please help i dont get this at all so please i will highly appreciate it .Thank youuu!!!
svlad2 [7]

Answer:

D

Step-by-step explanation:

definitely

6 0
1 year ago
Which expressions are equivalent to (5⋅x)⋅3 ? Drag and drop the equivalent expressions into the box.
marysya [2.9K]
<h2>Greetings!</h2>

Answer:

3⋅(5⋅x)

5⋅(x⋅3)

15x

Step-by-step explanation:

As the values are inside the brackets, it does not matter what side the (x3) is on, so 3⋅(5⋅x) is equivalent.


Multiplying the contents of the brackets in the third one (x * 3) by 5 gives the same value as 3 * (x * 5) so 5⋅(x⋅3) is also equivalent.


On multiplying the brackets out:

5 * x = 5x

5x * 3 = 15x

So 15x is also equivalent.


<h2>Hope this helps!</h2>
3 0
3 years ago
14 dollars for 9 books
Art [367]

Answer:

$0.64 per book

Step-by-step explanation:

8 0
3 years ago
Read 2 more answers
Se van a colocar mosaicos de 15m×0.30 m en un espacio que mide 3.2 m2. ¿Cuántos mosaicos completos se colocarán?
kati45 [8]

Answer:

tu aimes les hommes

Step-by-step explanation:

5 0
3 years ago
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