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Arlecino [84]
3 years ago
6

HELP!!! STATS!!!

Mathematics
1 answer:
Vadim26 [7]3 years ago
4 0

Answer:

The 99% confidence interval is   165.776  <  \mu <  180.224  

Step-by-step explanation:

From the question we are told that

     The sample size is  n  = 100

     The sample mean is  \=  x  =  173 \  days

      The population standard deviation is  \sigma =  28 \ days  

From the question we are told the confidence level is  99% , hence the level of significance is    

      \alpha = (100 - 99 ) \%

=>   \alpha = 0.01

Generally from the normal distribution table the critical value  of  \frac{\alpha }{2} is  

   Z_{\frac{\alpha }{2} } = 2.58

Generally the margin of error is mathematically represented as  

      E = Z_{\frac{\alpha }{2} } *  \frac{\sigma }{\sqrt{n} }

      E = 2.58  *  \frac{28 }{\sqrt{100} }

=>    E = 7.224

Generally 95% confidence interval is mathematically represented as  

      \= x -E <  \mu <  \=x  +E

=>     173 -7.224  <  \mu < 173 + 7.224    

=>     165.776  <  \mu < 180.224  

     

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Daniel [21]

Multiply all of the numbers together: 5 x 2 x 8 = 10 x 8 = 80 ways

3 0
3 years ago
Some scientists believe alcoholism is linked to social isolation. One measure of social isolation is marital status. A study of
frez [133]

Answer:

1) H0: There is independence between the marital status and the diagnostic of alcoholic

H1: There is association between the marital status and the diagnostic of alcoholic

2) The statistic to check the hypothesis is given by:

\sum_{i=1}^n \frac{(O_i -E_i)^2}{E_i}

3) \chi^2 = \frac{(21-33.143)^2}{33.143}+\frac{(37-41.429)^2}{41.429}+\frac{(58-41.429)^2}{41.429}+\frac{(59-46.857)^2}{46.857}+\frac{(63-58.571)^2}{58.571}+\frac{(42-58.571)^2}{58.571} =19.72

4) df=(rows-1)(cols-1)=(3-1)(2-1)=2

And we can calculate the p value given by:

p_v = P(\chi^2_{2} >19.72)=5.22x10^{-5}

And we can find the p value using the following excel code:

"=1-CHISQ.DIST(19.72,2,TRUE)"

Since the p value is lower than the significance level so then we can reject the null hypothesis at 5% of significance, and we can conclude that we have association between the two variables analyzed.

Step-by-step explanation:

A chi-square goodness of fit test "determines if a sample data matches a population".

A chi-square test for independence "compares two variables in a contingency table to see if they are related. In a more general sense, it tests to see whether distributions of categorical variables differ from each another".

Assume the following dataset:

                    Diag. Alcoholic   Undiagnosed Alcoholic    Not alcoholic    Total

Married                     21                              37                            58                116

Not Married              59                             63                            42                164

Total                          80                             100                          100              280

Part 1

We need to conduct a chi square test in order to check the following hypothesis:

H0: There is independence between the marital status and the diagnostic of alcoholic

H1: There is association between the marital status and the diagnostic of alcoholic

The level os significance assumed for this case is \alpha=0.05

Part 2

The statistic to check the hypothesis is given by:

\sum_{i=1}^n \frac{(O_i -E_i)^2}{E_i}

Part 3

The table given represent the observed values, we just need to calculate the expected values with the following formula E_i = \frac{total col * total row}{grand total}

And the calculations are given by:

E_{1} =\frac{80*116}{280}=33.143

E_{2} =\frac{100*116}{280}=41.429

E_{3} =\frac{100*116}{280}=41.429

E_{4} =\frac{80*164}{280}=46.857

E_{5} =\frac{100*164}{280}=58.571

E_{6} =\frac{100*164}{280}=58.571

And the expected values are given by:

                    Diag. Alcoholic   Undiagnosed Alcoholic    Not alcoholic    Total

Married             33.143                       41.429                        41.429                116

Not Married     46.857                      58.571                        58.571                164

Total                   80                              100                             100                 280

And now we can calculate the statistic:

\chi^2 = \frac{(21-33.143)^2}{33.143}+\frac{(37-41.429)^2}{41.429}+\frac{(58-41.429)^2}{41.429}+\frac{(59-46.857)^2}{46.857}+\frac{(63-58.571)^2}{58.571}+\frac{(42-58.571)^2}{58.571} =19.72

Part 4

Now we can calculate the degrees of freedom for the statistic given by:

df=(rows-1)(cols-1)=(3-1)(2-1)=2

And we can calculate the p value given by:

p_v = P(\chi^2_{2} >19.72)=5.22x10^{-5}

And we can find the p value using the following excel code:

"=1-CHISQ.DIST(19.72,2,TRUE)"

Since the p value is lower than the significance level so then we can reject the null hypothesis at 5% of significance, and we can conclude that we have association between the two variables analyzed.

7 0
3 years ago
Solve the equation <br>y=2x-4, 3x+y=11​
Ostrovityanka [42]

Answer:

(3, 2)

Step-by-step explanation:

Given the 2 equations

y = 2x - 4 → (1)

3x + y = 11 → (2)

Substitute y = 2x - 4 into (2)

3x + 2x - 4 = 11

5x - 4 = 11 ( add 4 to both sides )

5x = 15 ( divide both sides by 5 )

x = 3

Substitute x = 3 into (1) for corresponding value of y

y = (2 × 3) - 4 = 6 - 4 = 2

Solution is (3, 2)

5 0
2 years ago
Read 2 more answers
Joseph owns a hot dog stand and sells specialized hot dogs. He charges $1.50 for a plain hot dog and then an additional $0.50 fo
Lilit [14]

Hot Dog Stand

Let

C--------> total cost of the hot dog

x-------> is the number of toppings

we know that

C=0.5x+1.5

where

The slope of the linear equation is equal to 0.5\frac{\$}{topping}

The y-coordinate of the y-intercept of the linear function is equal to \$1.5

That means -------> This is the cost of the hot dog without topping  

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Let

C--------> total cost of the hamburger

x-------> is the number of toppings

we know that

C=0.25x+2.50

where

The slope of the linear equation is equal to 0.25\frac{\$}{topping}

The y-coordinate of the y-intercept of the linear function is equal to \$2.5

That means -------> This is the cost of the hamburger without topping

therefore

<u>the answer is</u>

The linear equation of the hamburger cost is equal to

C=0.25x+2.50


4 0
3 years ago
Read 2 more answers
PLEASE HELP!! Please show your work in explanation no nonsense or blank answers please ;)
krok68 [10]

Answer:

r = 4.908

Step-by-step explanation:

V  = 885

height (given in the picture) = 11.7

V = \pi r^2h

V = (3.14)(r^2)(h)

885 = (3.14)(r^2)(11.7)

885/3.14/11.7 = r^2

Take the square root and you get 4.908.

8 0
3 years ago
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