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Nadya [2.5K]
3 years ago
7

Does taking ginkgo tablets (i.e., and extract from a tree species) twice a day provide significant improvement in mental perform

ance? To investigate this issue, a researcher conducted a study with 150 adult subjects who took ginkgo tablets twice a day for a period of 6 months. At the end of the study, 200 variables related to the mental performance of the subjects were measured on each subject and the means compared to known means for these variables in the population of all adults. Nine of these variables were significantly better (in the sense of statistical significance) at the 5% level for the group taking the ginkgo tablets as compared to the population as a whole, and one variable was significantly better at the 1% level for the group taking the ginkgo tablets as compared to the population as a whole. Which of the following statements is the correct conclusion?
A. There is good statistical evidence that taking ginkgo tablets twice a day provides some improvement in mental performance.
B. These results would have provided good statistical evidence that taking ginkgo tablets twice a day provides some improvement in mental performance if the number of subjects had been larger. It is premature to draw statistical conclusions from studies in which the number of subjects is less than the number of variables measured.
C. There is good statistical evidence that taking ginkgo tablets twice a day provides improvement for the variable that was significant at the 1% level. We should be somewhat cautious about making claims for the variables that were significant at the 5% level.
D. These results do not provide good statistical evidence that taking ginkgo tablets twice a day provides some improvement in mental performance. If 200 tests are being performed at the 5% significance level, some are bound to show statistically significant results, even if the treatment does not have any effect. It is premature to draw statistical conclusions from this study in which the percentage of significant tests is about 5%.
Mathematics
1 answer:
Dmitriy789 [7]3 years ago
5 0

Answer:

D. These results do not provide good statistical evidence that taking ginkgo tablets twice a day provides some improvement in mental performance. If 200 tests are being performed at the 5% significance level, some are bound to show statistically significant results, even if the treatment does not have any effect. It is premature to draw statistical conclusions from this study in which the percentage of significant tests is about 5%.

Step-by-step explanation:

It is not right to just made a conclusive argument on a large population by considering the outcome of the analysis made on a sample of the population. In addition, based on the number of tests conducted with about 5% significance level, it is clear that this can not be used to draw the necessary conclusion.

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Replace with 16 − 2 and simplify. 1 , y = 16−2,2, (4,2), (−4,k), k, x-intercepts

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A spring is attatched at one end to support B and at the other end to collar A, as represented in the figure. Collar A slides al
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Step-by-step explanation:

cos θ = 3 / AB

When θ = 28°:

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AB = 3 / cos 28°

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When AB = 5.2:

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3 years ago
Two friends Ana and Juan are buying books by joining the History Book
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Answer:

Ana  spent $17  per book on average.

Juan  spent $14.78  per book on average.

y = $15 + 17x--------- equation 1

y= $10 + 14.78 x------------- equation 2

Step-by-step explanation:

Ana has to pay a yearly fee of $15 to join.

She spends a total of $525 for 30 books.

The amount spent on books = Total amount - yearly fee

                                                 = $525- $15= $510

Price per book on the average = $510/30= $ 17

Ana  spent $17  per book on average.

Juan has to pay a yearly fee of $10 to join.

He spends a total of $350 for 23 books.

The amount spent on books = Total amount - yearly fee

                                                 = $350- $10= $340

Price per book on the average = $340/23= $ 14.78≅ $15

Juan  spent $14.78  per book on average.

The function can be established if y gives the total cost and x gives the number of books

y = $15 + 17x--------- equation 1

y= $10 + 14.78 x------------- equation 2

Juan has a better deal because the yearly fee is less also the price per book is less.

8 0
3 years ago
What is the surface area of the figure shown?
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The surface area of the figure = 962 ft²

Step-by-step explanation:

The rectangle dimensions and its area given below

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12 x 7                2                   12 x 7 x 2 = 168

16 x 7                1                    16 x 7 = 112

12 x (16 + 5)     1                    12 x 21 = 252

16 x 12              1                    16 x 12 = 192

16 x 13              1                     16 x 13 = 208

Triangle dimensions

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b = 12  & h = 5       2                bh/2 = (12*5)/2  = 30

To find total area

Total area = 168 + 112 + 252 + 192 + 208 + 30 = 962 ft²

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It equals to 8.82 
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