Help!! So confused!

1 answer:

6 0

The series in the form of arithmetic progression
The notation of A.P is a, a+d, a+2d.....
The summation notation is â‘
In this series a=3, d=7
Then the summation of A.P is â‘ = n/2(2a+(n-1)d)
=18/2(2*3+ (18-1)7)
= 9(6+17(7))
=9(6+119)
=9(125)
= 1125
Hence the total number of beads is 1125

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Answer:

The 99% confidence interval for the proportion of all American adults who blame Barack Obama a great deal or a moderate amount for U.S. economic problems is (0.4894, 0.5706)..

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

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In which

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For this problem, we have that:

$n = 1004, \pi = 0.53$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.53 - 2.575\sqrt{\frac{0.53*0.47}{1004}} = 0.4894$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.53 - 2.575\sqrt{\frac{0.53*0.47}{1004}} = 0.5706$

The 99% confidence interval for the proportion of all American adults who blame Barack Obama a great deal or a moderate amount for U.S. economic problems is (0.4894, 0.5706)..

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3 years ago

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3 years ago

40 points and branliest