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c:ms:2020:schedule [2020/06/26 15:37] – [Week16 (June 22, 25)] hkimscilc:ms:2020:schedule [2020/06/27 13:29] hkimscil
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 ===== Concepts and ideas ===== ===== Concepts and ideas =====
- 
- 
 <WRAP box> <WRAP box>
 Some [[:b:r cookbook:basics|basics]] Some [[:b:r cookbook:basics|basics]]
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 ===== Concepts and ideas ===== ===== Concepts and ideas =====
-Do the following 
-<code>S1 <- c(89, 85, 85, 86, 88, 89, 86, 82, 96, 85, 93, 91,  
-        98, 87, 94, 77, 87, 98, 85, 89, 95, 85, 93, 93,  
-        97, 71, 97, 93, 75, 68, 98, 95, 79, 94, 98, 95) 
-S2 <- c(60, 98, 94, 95, 99, 97, 100, 73, 93, 91, 98,  
-        86, 66, 83, 77, 97, 91, 93, 71, 91, 95, 100,  
-        72, 96, 91, 76, 100, 97, 99, 95, 97, 77, 94,  
-        99, 88, 100, 94, 93, 86) 
-S3 <- c(95, 86, 90, 90, 75, 83, 96, 85, 83, 84, 81, 98,  
-        77, 94, 84, 89, 93, 99, 91, 77, 95, 90, 91, 87,  
-        85, 76, 99, 99, 97, 97, 97, 77, 93, 96, 90, 87,  
-        97, 88) 
-S4 <- c(67, 93, 63, 83, 87, 97, 96, 92, 93, 96, 87, 90,  
-        94, 90, 82, 91, 85, 93, 83, 90, 87, 99, 94, 88,  
-        90, 72, 81, 93, 93, 94, 97, 89, 96, 95, 82, 97) 
- 
-scores <- list(S1=S1,S2=S2,S3=S3,S4=S4)</code> 
- 
-  * find means for each element in "scores" in a list format 
-  * find standard deviation for each element in "scores" in a data frame format 
-  * find variance  for each element in "scores" in a data frame format without using "var" function 
- 
-<code>longdata<- c(-1.850152, -1.406571, -1.0104817, -3.7170704,  
-           -0.2804896, 0.9496313, 1.346517, -0.1580926, 1.6272786,  
-           -2.4483321, -0.5407272, -1.708678, -0.3480616, -0.2757667,  
-           -1.2177024)</code> 
-  * make "longdata" to a matrix whose size is  3 by 5 
-  * name columns "trial1, trial2, . . . . trial5" 
-  * name rows "subject1, subject2, subject3" 
-  * get means for each subject  
-  * attach the above data to the matrix data and name it "longtemp." 
-  * get standard deviation for each trial 
-  * attach the above data to the matrix data, "longtemp." 
- 
- 
-<code>suburbs <- read.csv("http://commres.net/wiki/_export/code/r/data_transformations?codeblock=15", head=T, sep=" ")</code> 
-  * get subrubs data  as the above 
-  * get population means by each state (listed in the data, suburbs) 
-    * use aggregate and refer to the below e.g. 
-<code>attach(Cars93) 
-aggregate(MPG.city ~ Origin, Cars93, mean)</code> 
-  * get population sum by each county with  tapply function.  
-  * tapply(number, byfactor, function) 
-  * how many counties are there? 
-  * Use Cars93 data, get MPG.city mean by Origin. 
- 
-__Using pnorm, qnorm__ 
-pnorm : get proportion out of normal distribution whose characteristics are mean and sd 
-<code>pnorm(84, mean=72, sd=15.2, lower.tail=FALSE)</code> 
-  * What is the value of  the below? 
-<code>pnorm(1)</code> 
-  * How would you get 68, 95, 99% from pnorm 
-      * use ?pnorm and see the default option 
- 
-  * generate 10 random numbers with runif function 
- 
-<code>year <- c(1900:2016)     # years in vector year 
-world.series <- data.frame(year)</code> 
-  * get 10 year samples out of world.series data with "sample" command 
-  * how would you get the sample sample again latter? 
- 
-<code>pnorm(110, mean=100, sd=10)</code> 
-  * What would be the result from the above? 
- 
-<code>library(MASS)       # load the MASS package  
-tbl = table(survey$Smoke, survey$Exer)  
-tbl                 # the contingency table</code>  
- 
-<code>summary(tbl) 
-</code> 
-  * read the above output and interpret 
-  * what about the below one? 
-<code>chisq.test(tbl)  
-</code> 
- 
-see first [[:chi-square test]] 
-see [[:b:r cookbook:chi-square test]] in r document space for more 
- 
-<code> library(MASS) 
- cardata <- data.frame(Cars93$Origin, Cars93$Type) 
- cardata 
-</code> 
-  * Can you say the types of cars are different by the Origins? 
- 
-<code>dur <- faithful$eruptions 
-dur</code> 
-  * make the above data into z-score (zdur). 
-  * get mean of the zdur 
-  * get sd of the zdur 
- 
-<code> 
-set.seed(1123) 
-x <- rnorm(50, mean=100, sd=15) 
-</code> 
-  * test x against population  mean 95. 
-  * test x against population  mean 99. 
-  * are they different from each other? 
-  * what would you do if you want to see the different result from the  second one? 
- 
-<code>a = c(65, 78, 88, 55, 48, 95, 66, 57, 79, 81) 
- 
-> t.test(a, mu=60) 
- 
- One Sample t-test 
- 
-data:  a 
-t = 2.3079, df = 9, p-value = 0.0464 
-alternative hypothesis: true mean is not equal to 60 
-95 percent confidence interval: 
- 60.22187 82.17813 
-sample estimates: 
-mean of x  
-     71.2  
-</code> 
-  * find the t critical value with function qt.  
-  * explain what happens in the next code 
-  * read (or remind) what pnorm and qnorm do. 
-<code>> s <- sd(x) 
-> m <- mean(x) 
-> n <- length(x) 
-> n 
-[1] 50 
-> m 
-[1] 96.00386 
-> s 
-[1] 17.38321 
-> SE <- s / sqrt(n) 
-> SE 
-[1] 2.458358 
-> E <- qt(.975, df=n-1)*SE 
-> E 
-[1] 4.940254 
-> m + c(-E, E) 
-[1]  91.0636 100.9441 
-> </code> 
- 
- 
-  * what's wrong with the below? 
-<code>t.test(x)</code> 
- 
-<code>> mtcars</code> 
-  * using aggregate, get mean for each trnas. type. 
-  * compare the difference of mileage between auto and manual cars. 
-    * use t.test (two sample) 
-    * "use var.equal=T" option 
- 
-<code>a = c(175, 168, 168, 190, 156, 181, 182, 175, 174, 179) 
-b = c(185, 169, 173, 173, 188, 186, 175, 174, 179, 180) 
-</code> 
-  * stack them into data c 
-  * convert colnames into score and trans 
-  * t.test score by trans with var.equal option true.  
-  * aov test 
-  * see  t.test t value, t = -0.9474 and F value,  F = ? 
  
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 +===== Assignment =====
 +그룹과제 내용수정 ----
 +그룹과제 내용을 아래와 같이 수정합니다. 
 +
 </WRAP> </WRAP>
 ====== Week16 (June 22, 25) ====== ====== Week16 (June 22, 25) ======
c/ms/2020/schedule.txt · Last modified: 2021/03/02 09:42 by hkimscil

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