1.29) The post-lunch dip is the drop in mental alertness after a midday meal. Does an extract of the leaves of the ginkgo tree reduce the post-lunch dip? Assign healthy people aged 18 to 4o to take either ginkgo extract or a placebo pill. After lunch, ask them to read seven pages of random letters and place an X over every e. Count the number of misses per line read. eBook Step 1: What is a placebo and why was one group given a placebo? True or False: A placebo is a much less concentrated ginkgo extract. A placebo allows researchers to asses the active concentration of ginkgo in the extract. O True O False
1.29) The post-lunch dip is the drop in mental alertness after a midday meal. Does an extract of the leaves of the ginkgo tree reduce the post-lunch dip? Assign healthy people aged 18 to 4o to take either ginkgo extract or a placebo pill. After lunch, ask them to read seven pages of random letters and place an X over every e. Count the number of misses per line read. eBook Step 1: What is a placebo and why was one group given a placebo? True or False: A placebo is a much less concentrated ginkgo extract. A placebo allows researchers to asses the active concentration of ginkgo in the extract. O True O False
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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1

Transcribed Image Text:1. (21.29) The post-lunch dip is the drop in mental alertness after a midday meal.
Does an extract of the leaves of the ginkgo tree reduce the post-lunch dip?
Assign healthy people aged 18 to 40 to take either ginkgo extract or a placebo pill.
After lunch, ask them to read seven pages of random letters and place an X over every e.
Count the number of misses per line read.
eBook
Step 1:
What is a placebo and why was one group given a placebo?
True or False:
A placebo allows researchers to asses the active concentration of ginkgo in the extract.
O True
O False
Step 2:
What is the double-blind method and why should it be used in this experiment?
Neither the subjects nor the researchers who worked with them knew who was getting ginkgo extract.
This prevents expectations or prejudices from affecting the evaluation of the effectiveness of the treatment.
The researchers who worked with the subjects did not know which of the subjects was getting ginkgo extract.
This prevents expectations from affecting the evaluation of the effectiveness of the treatment.
O The researchers and subjects did not meet each other, to prevent non relevant considerations in the evaluation of the effectiveness of the treatment.
The subjects did not know who was getting ginkgo extract.
This prevents expectations or prejudices from affecting the evaluation of the effectiveness of the treatment.
Step 3:
Here are summaries of performance after 13 weeks of either ginkgo extract or placebo:
Group
Group size
Мean
Std. dev
Ginkgo
21
0.06383 0.01462
Placebo
18
0.05342 0.01549
Is there a significant difference between the two groups?
Give the two sample test statistic.
Give your answer to 3 decimal places.

Transcribed Image Text:Step 4:
Give the P-value to evaluate if a significant difference exists between the two groups.
O 0.04 < P< 0.0o5
O 0.05 < P< 0.10
OP> 0.10
OP< 0.025
Step 5:
What do these data show about the effect of ginkgo extract?
O we have strong evidence, at the 1% level, that those who took gingko extract had more misses per line.
O The data do not give significant evidence, at the 5% level, that those who took gingko extract had more misses per line.
O we have significant evidence, at the 5% level, that ginkgo extract does not reduce post lunch dip.
O we have evidence, significant at the 5% level, that those who took gingko extract had more misses per line.
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