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--- b:head_first_statistics:visualization [2025/09/02 23:38] – [Histogram skewedness] hkimscil
+++ b:head_first_statistics:visualization [2026/09/01 23:14] (current) – [Scatter plot] hkimscil
@@ Line 91: / Line 91: @@
 </code>
 {{:b:head_first_statistics:pasted:20240904-082258.png}}
+<tabbox histogram.r>
+<code>
+dat.iq <- rnorm(1000, 100, 15)
+head(dat.iq)
+tail(dat.iq)
+head(dat.iq, n=12)
+tail(dat.iq, n=12)
+mean(dat.iq)
+sd(dat.iq)
+hist(dat.iq)
+hist(dat.iq, breaks=30, col='lightblue')
+set.seed(101)
+dat.iq <- rnorm(1000, 100, 15)
+head(dat.iq)
+tail(dat.iq)
+head(dat.iq, n=12)
+tail(dat.iq, n=12)
+mean(dat.iq)
+sd(dat.iq)
+hist(dat.iq)
+hist(dat.iq, breaks=30, col='lightblue')
+</code>
+<tabbox histogram.out>
+<code>
+> dat.iq <- rnorm(1000, 100, 15)
+> head(dat.iq)
+[1]  95.50853 103.02007  96.27211  93.36366  89.79188  64.85473
+> tail(dat.iq)
+[1] 105.04459 123.00613 106.41126  83.46953  90.00495 111.90697
+> head(dat.iq, n=12)
+ [1]  95.50853 103.02007  96.27211  93.36366  89.79188  64.85473  90.68743 103.88809 100.67983  80.20597  65.00360
+[12] 101.32801
+> tail(dat.iq, n=12)
+ [1]  93.27641  81.50208 119.88851  88.58754  74.30448  67.81593 105.04459 123.00613 106.41126  83.46953  90.00495
+[12] 111.90697
+>
+> mean(dat.iq)
+[1] 100.433
+> sd(dat.iq)
+[1] 14.82424
+>
+> hist(dat.iq)
+> hist(dat.iq, breaks=30, col='lightblue')
+>
+> set.seed(101)
+> dat.iq <- rnorm(1000, 100, 15)
+> head(dat.iq)
+[1]  95.10945 108.28693  89.87584 103.21539 104.66154 117.60949
+> tail(dat.iq)
+[1] 103.68009  96.19170 119.76069  83.43941 100.44177  87.48531
+> head(dat.iq, n=12)
+ [1]  95.10945 108.28693  89.87584 103.21539 104.66154 117.60949 109.28185  98.30899 113.75542  96.65111 107.89672
+[12]  88.07733
+> tail(dat.iq, n=12)
+ [1] 100.97563  88.75387 115.34405 105.59120 111.13368  98.84508 103.68009  96.19170 119.76069  83.43941 100.44177
+[12]  87.48531
+>
+> mean(dat.iq)
+[1] 99.47707
+> sd(dat.iq)
+[1] 14.38667
+>
+> hist(dat.iq)
+> hist(dat.iq, breaks=30, col='lightblue')
+</code>
+{{.:pasted:20260901-230508.png}}
+</tabbox>
 ====== Scatter plot ======
 <code>
@@ Line 132: / Line 206: @@
- <code># Simple Scatterplot
+<code># Simple Scatterplot
-attach(mtcars)
+plot(mtcars$wt, mtcars$mpg, main="Scatterplot Example",
-plot(wt, mpg, main="Scatterplot Example",
    xlab="Car Weight ", ylab="Miles Per Gallon ",
    pch=19)</code>
+{{.:pasted:20260901-230946.png?600}}
-{{:b:head_first_statistics:pasted:20240904-083016.png}}
 explanatory (설명) variable at x axis
@@ Line 148: / Line 220: @@
 <code># Add fit lines
-abline(lm(mpg~wt), col="red") # regression line (y~x)
+abline(lm(mtcars$mpg ~ mtcars$wt), col="red", lwd=2) # regression line (y~x)
 </code>
-{{:b:head_first_statistics:pasted:20240904-083157.png}}
+{{.:pasted:20260901-231239.png?600}}
+{{{.:pasted:20260901-231245.png}}
 Outlier에 대한 주의
 [{{:pearson-6.png? |}}]
@@ Line 249: / Line 321: @@
 {{:b:head_first_statistics:pasted:20250903-082513.png}}
 </WRAP>
+<WRAP clear/>
+====== Histogram Modality======
 <WRAP column half>
+Unimodal
 <code>
 ### unimodal data
@@ Line 267: / Line 342: @@
 {{:b:head_first_statistics:pasted:20250903-083409.png}}
 </WRAP>
 <WRAP clear/>
+Bimodal distribution
 <WRAP column half>
 <code>
@@ Line 290: / Line 366: @@
 </WRAP>
 <WRAP clear/>
 <WRAP column half>
@@ Line 301: / Line 376: @@
 # Parameters for the second normal distribution (Mode 2)
 m.2 <- 100
-sd.2 <- 8
+sd.2 <- 15
 m.3 <- 160
@@ Line 309: / Line 384: @@
 prop.1 <- 0.3
 # Mixing proportion for Mode 2
-prop.2 <- 0.4 # This is 1 - prop1
+prop.2 <- 0.6 # This is 1 - prop1
 # Mixing proportion for Mode 2
-prop.3 <- 0.3 # This is 1 - prop1
+prop.3 <- 1.0 # This is 1 - prop1
 # Number of samples to generate
@@ Line 345: / Line 419: @@
 </WRAP>
 <WRAP column half>
-{{:b:head_first_statistics:pasted:20250903-082247.png}}
+{{:b:head_first_statistics:pasted:20250908-082219.png}}
 </WRAP>
 <WRAP clear/>
@@ Line 351: / Line 425: @@
 ====== box plot ======
+<WRAP column half>
 <code>
 # Boxplot of MPG by Car Cylinders
@@ Line 359: / Line 433: @@
     ylab="Miles Per Gallon")
 </code>
-{{:c:ps1-1:2019:pasted:20190909-111438.png}}
+</WRAP>
+<WRAP column half>
+{{:c:ps1-1:2019:pasted:20190909-111438.png}}
+</WRAP>
+<WRAP clear/>
+====== see also ======
+https://r-graph-gallery.com/