Statistics for Decision Making Week 1 Lecture
Download as PPTX, PDF4 likes5,720 views
The document outlines key statistical concepts for a Math 221 course, including the distinction between population and sample, types of data, and methods of sampling. It explains various statistical measures such as quartiles, mean, median, mode, and standard deviation, along with instructions for using Excel functions to compute them. It also discusses identifying outliers in data based on standard deviations from the mean.
Statistics for Decision Making Week 1 Lecture
- 1. Lecture 1Math 221 Statistics for Decision MakingProfessor HeardLecturerAll materials © BN Heard and can not be copied without permission. Visit the Stat Cave online atwww.facebook.com/statcave
- 2. The following data represents the Discussion Board assignment scores for all of my Math 221 students. Would this be a population or a sample?(Scores out of 35 points)
- 3. The following data represents the Discussion Board assignment scores for all of my Math 221 students. Would this be a population or a sample?(Scores out of 35 points)This would be a population since the data is from ALL of my students.Samples are “subsets” of populations.(c) BN Heard www.facebook.com/statcave
- 4. The following data represents the number of children each of my Math 221 students have. Would this data set be qualitative or quantitative?(Number of Children)
- 5. The following data represents the number of children each of my Math 221 students have. Would this data set be qualitative or quantitative?(Number of Children)This would be quantitative data since we are dealing with numbers havingmeaning.(c) BN Heard www.facebook.com/statcave
- 6. The following data set represents the DB scores of 2 students randomly chosen from each of a total of 10 Statistics classes. What type of data set(or sampling) would this represent?
- 7. Know the difference in Sampling TechniquesRandom (simply picking where every member has an equal chance – drawing out of a bag – generating random numbers)
- 8. Stratified (dividing your population into strata and then picking a certain number from each strata)
- 9. Systematic (picking every nth one – for example testing every 20th unit off of an assembly line)
- 10. Convenience (just asking who is available or who is listening, not making an effort to get a true sample)
- 11. Cluster (dividing the population into clusters and sampling everyone in one or two of the clusters)(c) BN Heard www.facebook.com/statcave
- 12. The following data set represents the DB scores of 2 students randomly chosen from each of a total of 10 Statistics classes. What type of data set(or sampling) would this represent?This would be stratified sampling since we divided the population intoStrata (classes) and then randomly selected two from each.(c) BN Heard www.facebook.com/statcave
- 13. The following table of data represents the weight of 16 randomly selecteddogs in my neighborhood.Looking only at row 2, determine the class width, class boundaries andmidpoint.
- 14. Looking only at row 2, determine the class width, class boundaries andmidpoint.Class Width12-4 = 8You could have just as easily said 20-12,28-20 or 36-28 and still gotten 8.(c) BN Heard www.facebook.com/statcave
- 15. Looking only at row 2, determine the class width, class boundaries andmidpoint.The class boundaries for row 2 would be 11.5 and 19.5, simply subtract .5 from the lower and add .5 to the upper.(c) BN Heard www.facebook.com/statcave
- 16. Looking only at row 2, determine the class width, class boundaries andmidpoint.The midpoint for row 2 would be 15.5, just add (12+19) and divide by 2.Similarly the midpoint for row 5 would be 39.5(c) BN Heard www.facebook.com/statcave
- 17. The histogram below describes the height of 25 students. Looking only at the 64-65 group, determine the class width, class boundaries and midpoint.53-5455-5758-5960-6162-6364-6566-6768-6970-7172-73
- 18. The histogram below describes the height of 25 students. Looking only at the 64-65 group, determine the class width, class boundaries and midpoint.53-5455-5758-5960-6162-6364-6566-6768-6970-7172-73Class width would be 2, because 64 minus 62 is 2.Class boundaries would be 63.5 and 65.5Midpoint would be 64.5 because (64+65)/2 = 64.5(c) BN Heard www.facebook.com/statcave
- 19. The following is a sample of discussion board scores for a group of students. Find the first quartile, median and third quartile(c) BN Heard www.facebook.com/statcave
- 20. The following is a sample of discussion board scores for a group of students. Find the first quartile, median and third quartile. Input data input an Excel column, if the data is not provided.Etc.(c) BN Heard www.facebook.com/statcave
- 21. To find the first quartile use the quartile function in Excel to get 23.25To find the median use the median function in Excel to get 29.00. Note this is also the second quartileTo find the third quartile use the quartile function in Excel to get 35.00(c) BN Heard www.facebook.com/statcave
- 22. The following is a random sample of module scores for a group of students. Find the mean, median and mode.(c) BN Heard www.facebook.com/statcave
- 23. The following is a random sample of module scores for a group of students. Find the mean, median and mode. Input data input an Excel column, if the data is not provided. Ordering is a good idea. Use the Data Tab, select “Sort.”(c) BN Heard www.facebook.com/statcave
- 24. To find the mean use the “average” function in Excel to get 17.375, if rounded to the nearest whole number this would be simply 17.To find the median use the “median” function in Excel to get 19. To find the mode VISUALLY INSPECT THE DATA TO FIND 20 AS THE MODE.NOTE: WITH MULTIPLE MODES, EXCEL WILL ONLY RETURN ONE MODE.(c) BN Heard www.facebook.com/statcave
- 25. The following is a random sample of module scores for a group of students. Find the standard deviation.(c) BN Heard www.facebook.com/statcave
- 26. To find the standard deviation for a sample, use the “stdev” function in Excel to get 3.703602 or 3.7 rounded to one decimal place.Note: Use “stdev” for samples and “stdevp” for populations.(c) BN Heard www.facebook.com/statcave
- 27. The following is a random sample of exam scores for a group of students. The mean is 91.2 and the standard deviation is 13.0. Determine if there are any outliers, defining an outlier as a data point outside of the mean +/- 2 standard deviations.(c) BN Heard www.facebook.com/statcave
- 28. The following is a random sample of exam scores for a group of students. The mean is 91.2 and the standard deviation is 13.0. Determine if there are any outliers, defining an outlier as a data point outside of the mean +/- 2 standard deviations.91.2 – 2(13) = 65.2 and 91.2 + 2(13) = 117.2.The only scores outside of these bounds are 52 and 58, thus they are the only two outliers.(c) BN Heard www.facebook.com/statcave65.2117.2
- 29. The following is a random sample of exam scores for a group of students. The mean is 91.2 and the standard deviation is 13.0. How many standard deviations is a score of 88 from the mean?(c) BN Heard www.facebook.com/statcave
- 30. The following is a random sample of exam scores for a group of students. The mean is 91.2 and the standard deviation is 13.0. How many standard deviations is a score of 88 from the mean?(88-92.1)/13 = -0.24615 or -0.25 rounded to two decimal places.This could also be described as “0.25 below the mean.”(c) BN Heard www.facebook.com/statcave
- 31. Visit me on Facebook at www.facebook.com/statcaveYou DO NOT have to have a Facebook account to view these, but I would like having you “Like” the Stat Cave if you do.I post things from time to time, both informative and fun.You can download these charts by clicking the “Download” button above the charts.(c) BN Heard www.facebook.com/statcave