2012-09-12 Class Notes

Measurement and measurement bias

Sampling and sampling bias

Random sampling

In-Class Activity

fetchData("simulate.r")
## Retrieving from http://www.mosaic-web.org/go/datasets/simulate.r
## [1] TRUE

Instructor's write up

Graphics about distributions

(from Monday)

Numerical summaries of distributions (from Monday)

mean, variance, and standard deviation

other measures (e.g., IQR, median, 95% coverage)

In-class activity on the properties of the various measures.

What do your fellow students know about statistics

ks = fetchData("/Users/kaplan/Dropbox/Stat155Fall2012/knowledge-survey-2012-09-11.csv")
## Complete file name given.  No searching necessary.
for (item in levels(ks$ProblemItem)) {
    print(item)
    print(tally(~as.character(AnswerContents), data = subset(ks, ProblemItem == 
        item)))
    print("")
}
## [1] "ANCOVA"
## 
##  None  Some Total 
##    48    16    64 
## [1] ""
## [1] "ANOVA"
## 
## Complete     None     Some    Total 
##        1       32       31       64 
## [1] ""
## [1] "DF"
## 
## Complete     None     Some    Total 
##        3       33       27       63 
## [1] ""
## [1] "Ftest"
## 
##  None  Some Total 
##    60     3    63 
## [1] ""
## [1] "Hnull"
## 
## Complete     None     Some    Total 
##       22       20       20       62 
## [1] ""
## [1] "LA"
## 
##         10-12           4-6           6-9 AP\n   course       College 
##            14             5            14             1            11 
##         Never         Total 
##            19            64 
## [1] ""
## [1] "LSQ"
## 
## Complete     None     Some    Total 
##        9       35       19       63 
## [1] ""
## [1] "TypeI"
## 
## Complete     None     Some    Total 
##        2       44       17       63 
## [1] ""
## [1] "algebra"
## 
##         10-12 AP\n   course       College         Never         Total 
##             7             1            35            21            64 
## [1] ""
## [1] "bayes"
## 
## Complete     None     Some    Total 
##        4       47       12       63 
## [1] ""
## [1] "boot"
## 
##  None  Some Total 
##    61     2    63 
## [1] ""
## [1] "bwplot"
## 
##         10-12           4-6           6-9 AP\n   course       College 
##             9            15            23             4             2 
##         Never         Total 
##            11            64 
## [1] ""
## [1] "calc"
## 
##         10-12           4-6           6-9 AP\n   course       College 
##            20             3            31             4             1 
##         Never         Total 
##             4            63 
## [1] ""
## [1] "coll"
## 
## Complete     None     Some    Total 
##        1       46       15       62 
## [1] ""
## [1] "cond"
## 
## Complete     None     Some    Total 
##        1       50       12       63 
## [1] ""
## [1] "confI"
## 
## Complete     None     Some    Total 
##        7       35       20       62 
## [1] ""
## [1] "cprob"
## 
##         10-12           4-6           6-9 AP\n   course       College 
##            19             3             9             4             1 
##         Never         Total 
##            28            64 
## [1] ""
## [1] "cumu"
## 
## Complete     None     Some    Total 
##        3       44       16       63 
## [1] ""
## [1] "dummy"
## 
## Complete     None     Some    Total 
##        1       46       16       63 
## [1] ""
## [1] "excel"
## 
##         10-12           4-6           6-9 AP\n   course       College 
##            20             1            19             2            12 
##         Never         Total 
##            10            64 
## [1] ""
## [1] "exp"
## 
## Complete     None     Some    Total 
##       20       12       30       62 
## [1] ""
## [1] "hist"
## 
##           1-3         10-12           4-6           6-9 AP\n   course 
##             3            12            15            20             3 
##       College         Never         Total 
##             1            10            64 
## [1] ""
## [1] "intrct"
## 
## Complete     None     Some    Total 
##        1       48       14       63 
## [1] ""
## [1] "lincomb"
## 
## Complete     None     Some    Total 
##       11       35       17       63 
## [1] ""
## [1] "logist"
## 
##  None  Some Total 
##    50    13    63 
## [1] ""
## [1] "lreg"
## 
## Complete     None     Some    Total 
##       18       20       26       64 
## [1] ""
## [1] "mTerm"
## 
## Complete     None     Some    Total 
##        1       50       12       63 
## [1] ""
## [1] "main"
## 
## Complete     None     Some    Total 
##        1       48       13       62 
## [1] ""
## [1] "mmm"
## 
##     1-3   10-12     4-6     6-9 College   Never   Total 
##       7       1      33      14       1       2      58 
## [1] ""
## [1] "normal"
## 
##         10-12           6-9 AP\n   course       College         Never 
##            29            14             6             7             8 
##         Total 
##            64 
## [1] ""
## [1] "ortho"
## 
## Complete     None     Some    Total 
##        9       40       13       62 
## [1] ""
## [1] "out"
## 
## Complete     None     Some    Total 
##       45        5       14       64 
## [1] ""
## [1] "pVal"
## 
## Complete     None     Some    Total 
##       12       26       26       64 
## [1] ""
## [1] "perc"
## 
## Complete     None     Some    Total 
##       39        1       24       64 
## [1] ""
## [1] "prob"
## 
##           1-3         10-12           4-6           6-9 AP\n   course 
##             5            26            13            17             1 
##       College         Never         Total 
##             1             1            64 
## [1] ""
## [1] "program"
## 
##           6-9 AP\n   course       College         Never         Total 
##             1             1            24            38            64 
## [1] ""
## [1] "rand"
## 
## Complete     None     Some    Total 
##       15       24       24       63 
## [1] ""
## [1] "rank"
## 
##  None  Some Total 
##    57     6    63 
## [1] ""
## [1] "rcoef"
## 
## Complete     None     Some    Total 
##       11       17       36       64 
## [1] ""
## [1] "regres"
## 
##         10-12           6-9 AP\n   course       College         Never 
##            21             6             7            13            17 
##         Total 
##            64 
## [1] ""
## [1] "resid1"
## 
## Complete     None     Some    Total 
##        9       24       30       63 
## [1] ""
## [1] "sResid"
## 
## Complete     None     Some    Total 
##        6       39       18       63 
## [1] ""
## [1] "sampD"
## 
## Complete     None     Some    Total 
##        5       25       33       63 
## [1] ""
## [1] "scatter"
## 
##         10-12           4-6           6-9 AP\n   course       College 
##            11            18            26             3             3 
##         Never         Total 
##             3            64 
## [1] ""
## [1] "sd"
## 
##    10-12      6-9  College Complete     None     Some    Total 
##        2        1        1       30        6       24       64 
## [1] ""
## [1] "sig"
## 
## Complete     None     Some    Total 
##        8       36       19       63 
## [1] ""
## [1] "skew"
## 
## Complete     None     Some    Total 
##        7       34       22       63 
## [1] ""
## [1] "subsp"
## 
## Complete     None     Some    Total 
##        8       31       24       63 
## [1] ""
## [1] "t"
## 
##           1-3         10-12           6-9 AP\n   course       College 
##             1            11             1             9            13 
##         Never         Total 
##            29            64 
## [1] ""
## [1] "tTest"
## 
## Complete     None     Some    Total 
##        4       32       28       64 
## [1] ""