Transcript Vocabulary used in this Lesson

Confidence Intervals
Estimating Ability with Confidence
Intervals
Vocabulary used in this Lesson
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Margin of Error
Confidence Interval
Sample Mean
Standard Deviation
Confidence Interval
• An interval of plausible
values where an Data
point may fall
– An interval is better than
single value because of
chances of accuracy
have increased
Confidence Intervals
• Three very common
intervals:
– 90%
–95%
– 99%
Interval
Z-score
Interpreting Confidence Intervals
• About 95% of all the intervals we construct
will contain the athlete’s ability
• “We are 95% confident that the interval of
plausible values from _________ to
_________ contains ____________’s ability
___________________________”
General Form for Confidence Interval
Margin of Error
Upper Endpoint – Observed Performance
OR
Observed Performance – Lower Endpoint
Calculating a Confidence Interval for a
Proportion
Calculating a Confidence Interval for a
mean
Lawn Weeds
A survey of 1898 adults with
lawns conducted by Harris
Interactive Poll found that
45% of the adults said that
dandelions were the toughest
weeds to control in their
yards. Find the 95%
confidence interval of the
true proportion who said that
dandelions were the toughest
weeds to control in their
yards.
Lawn Weeds
Hence you can say with ______
confidence that the true percentage
of adults who consider dandelions
the toughest weeds to control in
their lawns is between
___________ and _________.
Perry Como Fans
Fifty-six percent of
respondents to an online
poll said that they were
Perry Como fans. If 982
randomly selected people
responded to this poll,
what is the true
proportion of all local
residents who are Perry
Como fans? Estimate at
the 95% confidence level.
Perry Como
Hence you can say with ______
confidence that the true percentage
of___________________________
_____________________________
________is between ___________
and _________.
• Example 1:
https://www.youtube.com/watch?v=dNfpsVLa
aEE
Continue working on examples
KNOCKOUT
1. What are the three most
common confidence intervals?
A.10%, 100% and 1000%
B.90%, 95% and 99%
C.80%, 90% and 100%
D.85%, 95% and 100%
2. What is the only confidence interval
we deal with in this course?
A.100%
B.99%
C.95%
D.90%
3. What is the meaning of 𝑝̂?
A. Ability (true proportion of successes)
B. Performance (observed proportion of
successes)
C. Sample size
D. Confidence Interval
4. What is the meaning of 𝑝̂?
A. Ability (true proportion of successes)
B. Performance (observed proportion of
successes)
C. Sample size
D. Confidence Interval