Math 10 Name:
Chapter 8 Lab: Confidence Intervals
The Age of a Penny
Student Learning Outcomes:
• Students will use sample data to find confidence intervals for an unknown
population mean.
Materials:
• A roll of 50 pennies OR use the attached data sheet.
Procedure:
• Students will compute various statistics using the age of pennies.
• Student will use their sample data to form confidence intervals for the
population mean age of pennies in circulation.
1. Organize the data by using a stemplot of the ages.
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From Probability to Inference
Project 9 THE AGE OF A PENNY
Have you ever wondered how long coins stay in circulation? Are you a
collector? You each have a tube of pennies. Your first task is to form a
distribution of their ages.
1. Organize the data by using a stemplot of the ages. Split the stems to
give sufficient stems to the data.
2. What is the shape of the distribution? Why do you think it is this
shape?
3. Did you find any outliers?
4. Do you think the distribution of all pennies in circulation is similar to
your sample?
5. List the characteristic assumptions for the Central Limit Theorem, and
decide if they are satisfied by your distribution.
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2
2. What is the shape of the distribution?
3. Do you think the distribution of all pennies in circulation is similar to
your sample?
4. Find the mean and standard deviation of the ages of the pennies in you
sample.
Mean= S.D.= n=
5. Use your results to construct a 95% confidence interval for the mean
age of pennies in circulation. In words, explain what this confidence interval
means.
6. What is the E
or Bound for the Mean for the 95% confidence interval?
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7. Use your results to construct a 98% confidence interval for the mean
age of pennies in circulation. In words, explain what this confidence interval
means.
8. What is the E
or Bound for the Mean for the 98% confidence inter-
val?
4
Age of 50 pennies.
1995
2018
2006
2008
2016
1972
2010
1998
2017
1982
2014
1976
2012
2004
1983
1984
2015
1987
2001
1945
1990
2014
1989
1980
1996
2015
2014
2016
1982
1974
2014
2019
2002
1999
1987
2017
2015
1984
1988
1996
2016
2015
1999
2004
2014
2011
1985
2015
1999
1979