Week 3 Lecture Math 221
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This document provides a review for a week 3 quiz in a math 221 course. It summarizes key topics covered, including data collection methods, descriptive and inferential statistics, qualitative and quantitative data, sampling techniques, populations and samples, standard deviation and variance, regression equations, correlation coefficients, stem-and-leaf plots, and frequency distributions. Examples are provided for regression equations, correlation coefficients, and constructing a stem-and-leaf plot from frequency data. Students are directed to additional resources on Facebook for further assistance.
Week 3 Lecture Math 221
- 1. Week 3 Quiz Review for Math 221 B. Heard (These may not be copied, reproduced, or posted in an online classroom without my permission. Students may download one copy for personal use.)
- 2. Week 3 Quiz Review • Data Collection – Sampling – Census – Experiments – Simulations – Etc.
- 3. Week 3 Quiz Review • Descriptive & Inferential Statistics – Know the difference – Descriptive - This is a set of methods to describe data that we have collected. – Inferential - This is a set of methods used to make a generalization, estimate, prediction or decision.
- 4. Week 3 Quiz Review • Know the difference between Qualitative and Quantitative Data
- 5. Week 3 Quiz Review • Types of Sampling – Random – Stratified – Cluster – Systematic – Convenience
- 6. Week 3 Quiz Review • Populations and Samples – Parameters and Statistics
- 7. Week 3 Quiz Review • Standard Deviation and Variance – How to calculate and mathematical relationship. – Variance is the Standard Deviation squared. – Standard Deviation is the square root of the Variance.
- 8. Week 3 Quiz Review • Be able to get a regression equation. • Example – Data (4, 30), (4,35), (5,36), (6,42), (8,48)
- 9. Week 3 Quiz Review • Be able to get a regression equation. • Example – Data (4, 30), (4,35), (5,36), (6,42), (8,48)
- 10. Week 3 Quiz Review • Be able to get a regression equation. • Example – Data (4, 30), (4,35), (5,36), (6,42), (8,48)
- 11. Week 3 Quiz Review • Be able to get a regression equation. • Example – Data (4, 30), (4,35), (5,36), (6,42), (8,48) This would be written as y = 3.982x + 16.70
- 12. Week 3 Quiz Review • Use a multiple regression equation. • Plug and Chug • y = -6.5 +12a + 5.1 b where a is test score and b is a competency score. y predicts the person’s score on a job test. • Predict a job test score for a person who made a 50 on the test and got a 7 as a competency score. • y = -6.5 +12(50) + 5.1 (7) • Y = 629.2
- 13. Week 3 Quiz Review • Correlation Coefficients, also noted as “r” • Range from -1 to +1 • .75 to 1 is strong • .5 to .75 is moderate • .25 to .5 is weak • 0 to .25 is very weak (closer to zero, almost none) • + would be positive correlation, - would be negative correlation • For example, -0.58 would be moderate negative correlation
- 14. Week 3 Quiz Review • Be able to create a stem and leaf plot and determine descriptive statistics. • Mean • Median • Mode • Range • Variance • Standard Deviation • Use Minitab!
- 15. Week 3 Quiz Review • Identify Class Width • Identify Midpoint of certain classes • Identify class boundaries • Give the relative frequency • Fishing Tournament Data below is an example Number of Fish Frequency 0-7 9 8-15 15 16-23 12 24-31 3
- 16. Week 3 Quiz Review • Class Width is 8 Number of Fish Frequency 0-7 9 8-15 15 16-23 12 24-31 3 8-0 = 8, or you could have said 15 – 7 = 8, or count on your fingers, 0,1,2,3,4,5,6,7 (There are eight numbers, don’t let it fool you)
- 17. Week 3 Quiz Review • Midpoint of second class is 11.5 Number of Fish Frequency 8+15 = 23 0-7 9 divided by 2 8-15 15 gives you 11.5 16-23 12 24-31 3
- 18. Week 3 Quiz Review • What are the class boundaries of the third class? 15.5 and 23.5 Number of Fish Frequency 0-7 9 8-15 15 Subtract .5 from 16-23 12 the lower to get 24-31 3 15.5 and add .5 to the upper to get 23.5
- 19. Week 3 Quiz Review • Give the relative frequency of all classes Number of Fish Frequency Relative Frequency 0-7 9 9/39 8-15 15 15/39 16-23 12 12/39 24-31 3 3/39 Total of 39
- 20. Week 3 Quiz Review • Come see me at the “Statcave” • www.facebook.com/statcave • You DO NOT have to be a Facebook person to see these. • If you are, become a fan. • IT IS NOT REQUIRED TO BE ON FACEBOOK. IT’S SOMETHING I DO FOR FUN. • I post charts there because it is easy for me to do.