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Unformatted text preview: 0%, so our probability is not small enough to be considered unusual.
Which one is your conclusion “in context” (put an “X” next to your choice):
“There is not sufficient evidence at the 0.10 significance level to
support the claim that the percentage of females ordering merchandise
or services by phone has declined from the 2005 level.”
“There is sufficient evidence at the 0.10 significance level to support
the claim that the percentage of females ordering merchandise or
services by phone has declined from the 2005 level.”
b) Find a 95% confidence interval for the proportion of all females who have
ordered merchandise or services by phone in the last 12 months.
The name of the TI83/84 calculator function you will be using: 1PropZInt State your answer in words:
We are 95% confident that the population proportion (the proportion if ALL females who have
ordered merchandise or services by phone in the last 12 months) is between 33.941% and 42.459%.
Note that our hypothesized population proportion of 39.4% is in this interval, that's why our
hypothesis test did not reject it. c) What would a Type I Error be in this case? (You need to mention H0 and H1 in
your answer – i.e. Just saying “False Alarm” or “Missed Opportunity” is NOT
enough). We conclude "Reject H0 and Accept H1", but we are wrong just because of sampling
error. So the proportion if ALL females who have ordered merchandise or services
by phone in the last 12 months is 39.4%, but we said it was less than this. This is a
False Alarm. The Null Hypothesis was correct but we rejected it.
d) What would a Type II Error be in this case? (You need to mention H0 and H1 in
your answer – i.e. Just saying “False Alarm” or “Missed Opportunity” is NOT
enough). We conclude "Failed to Reject H0", but we are wrong just because of sampling error.
So the proportion if ALL females who have ordered merchandise or services by
phone in the last 12 months is less than 39.4%, but we failed to catch it. This is a
Missed Opportunity.
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This note was uploaded on 11/21/2013 for the course MTH 243 taught by Professor Dr.kim during the Winter '08 term at Southern Oregon.
 Winter '08
 DR.KIM
 Statistics

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