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1. |
Is a histogram an adequate graph to
demonstrate the proportions of individuals' voting
intention for the responses of question of "In the next
presidential elections, I intend to vote for .........?
Why? |
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2. |
Use a proper graphical presentation to
summarize the proportion of individuals' voting
intention, and find out the proportion of
individuals who intend to vote for "Republican". |
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3. |
Is there a difference between college
female and male on the degree of importance
of the issues of "Education", "Economy" and
"International policy"? Use appropriate graphical tools
and summary table to summarize your findings and give a
brief discussion. |
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4. |
Consider the issue on social security and
redefine the responses into two categories.
- Not important:0=Unimportant or not
at all important.
- Important:1=Important or very
important.
Now, summarize the proportion of
individuals in the sample who indicated "social
security" as "Important". This is an estimate of the
population proportion of college voters.
- Obtain a 90%confidence interval for
the proportion of college voters who view
"social
security" is important.
- Obtain a 99% confidence interval
for the proportion of college voters who view
"social
security" is important.
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5. |
Is there a significantly lower proportion
of college students who view "social security"
as an
important issue by comparing with voters who are 50
years or older? Suppose
that it has been known to the
public that the population proportion of individuals who
are 50 years or older who view "social security"
as an important issue is .8. Conduct a proper test of
hypothesis and draw a conclusion.
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6. |
Online shopping is becoming more popular.
In order to attract more customers, a
company decided to
completely redesign their online store. A study was
conducted to investigate the proportion of customers
purchasing online. The store has collected the
proportion of individuals who purchased. Before the
redesign, the proportion of
individuals who actually
purchased was known to be 8%. After the redesign, the
store decided to collect at random 1000 customers'
purchasing status in three month period.
From this 1000
randomly selected customers, the number of individuals
who purchased was 92.
- Use this sample information to
obtain a 95% confidence interval of the
proportion of individuals who purchased after
the redesign.
- Comparing this sample with the
known proportion before the redesign, conduct a proper
test of hypotheses to see if the proportion of
purchasing was significantly higher after the redesign
using x=1%.
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