Untitled

# 建立資料框 (Data Frame)
df <- data.frame(
  Name = c("張青松", "王奕翔", "田新雨", "徐麗娜", "張志傑", 
           "趙穎睿", "王智強", "宋媛婷", "袁四方", "張建國"),
  Statistic = c(68,85,74,88,63,78,90,80,58,63),
  Math = c(85,91,74,100,82,84,78,100,51,70),
  Japanese = c(84,63,61,49,89,51,59,53,79,91),
  Management = c(89,76,80,71,78,60,72,73,91,85),
  Accounting = c(86,66,69,66,80,60,66,70,85,82)
)

# 查看資料
df

##      Name Statistic Math Japanese Management Accounting
## 1  張青松        68   85       84         89         86
## 2  王奕翔        85   91       63         76         66
## 3  田新雨        74   74       61         80         69
## 4  徐麗娜        88  100       49         71         66
## 5  張志傑        63   82       89         78         80
## 6  趙穎睿        78   84       51         60         60
## 7  王智強        90   78       59         72         66
## 8  宋媛婷        80  100       53         73         70
## 9  袁四方        58   51       79         91         85
## 10 張建國        63   70       91         85         82

# ------------------------
# 1. 各科莖葉圖 (Stem-and-leaf plot)
# ------------------------
stem(df$Statistic)

## 
##   The decimal point is 1 digit(s) to the right of the |
## 
##   5 | 8
##   6 | 338
##   7 | 48
##   8 | 058
##   9 | 0

stem(df$Math)

## 
##   The decimal point is 1 digit(s) to the right of the |
## 
##    5 | 1
##    6 | 
##    7 | 048
##    8 | 245
##    9 | 1
##   10 | 00

stem(df$Japanese)

## 
##   The decimal point is 1 digit(s) to the right of the |
## 
##   4 | 9
##   5 | 139
##   6 | 13
##   7 | 9
##   8 | 49
##   9 | 1

stem(df$Management)

## 
##   The decimal point is 1 digit(s) to the right of the |
## 
##   6 | 0
##   7 | 12368
##   8 | 059
##   9 | 1

stem(df$Accounting)

## 
##   The decimal point is 1 digit(s) to the right of the |
## 
##   6 | 06669
##   7 | 0
##   8 | 0256

# ------------------------
# 2. 基本統計量 (Mean / Max / Min)
# ------------------------
mean(df$Statistic)

## [1] 74.7

max(df$Statistic)

## [1] 90

min(df$Statistic)

## [1] 58

mean(df$Math)

## [1] 81.5

max(df$Math)

## [1] 100

min(df$Math)

## [1] 51

# ------------------------
# 3. 標準差 (Standard Deviation)
# ------------------------
sd(df$Statistic)

## [1] 11.32402

sd(df$Math)

## [1] 14.62304

sd(df$Japanese)

## [1] 16.25115

# ------------------------
# 4. 百分位數 (Quantiles)
# ------------------------
quantile(df$Statistic)

##    0%   25%   50%   75%  100% 
## 58.00 64.25 76.00 83.75 90.00

quantile(df$Math)

##    0%   25%   50%   75%  100% 
##  51.0  75.0  83.0  89.5 100.0

quantile(df$Japanese)

##    0%   25%   50%   75%  100% 
## 49.00 54.50 62.00 82.75 91.00

quantile(df$Management)

##    0%   25%   50%   75%  100% 
## 60.00 72.25 77.00 83.75 91.00

quantile(df$Accounting)

##   0%  25%  50%  75% 100% 
## 60.0 66.0 69.5 81.5 86.0