A dataset containing chemical composition measurements from 25 tobacco leaf samples. This dataset is commonly used for demonstrating multivariate regression analysis and exploring relationships between chemical components and burn rate.
Usage
data(tobacco)Format
A data frame with 25 rows and 9 variables:
- cigarette
Numeric. Rate of cigarette burn in inches per 1000 seconds.
- sugar
Numeric. Percentage of sugar content in the leaf.
- nicotine
Numeric. Percentage of nicotine content.
- nitrogen
Numeric. Percentage of nitrogen content.
- chlorine
Numeric. Percentage of chlorine content.
- potassium
Numeric. Percentage of potassium content.
- phosphorus
Numeric. Percentage of phosphorus content.
- calcium
Numeric. Percentage of calcium content.
- magnesium
Numeric. Percentage of magnesium content.
Source
Anderson, R. L. and Bancroft, T. A. (1952), Statistical Theory in Research, McGraw-Hill Book Company, Inc., New York, NY.
Details
This dataset is particularly useful for:
Demonstrating multivariate regression analysis
Studying relationships between chemical composition and burn rate
Analyzing correlations between different chemical components
Teaching statistical methods in agricultural research
Examples
# Load the dataset
data(tobacco)
# View the first few rows
head(tobacco)
#> cigarette sugar nicotine nitrogen chlorine potassium phosphorus calcium
#> 1 1.55 20.05 1.38 2.02 2.90 2.17 0.51 3.47
#> 2 1.63 12.58 2.64 2.62 2.78 1.72 0.50 4.57
#> 3 1.66 18.56 1.56 2.08 2.68 2.40 0.43 3.52
#> 4 1.52 18.56 2.22 2.20 3.17 2.06 0.52 3.69
#> 5 1.70 14.02 2.85 2.38 2.52 2.18 0.42 4.01
#> 6 1.68 15.64 1.24 2.03 2.56 2.57 0.44 2.79
#> magnesium
#> 1 0.91
#> 2 1.25
#> 3 0.82
#> 4 0.97
#> 5 1.12
#> 6 0.82
# Summary statistics
summary(tobacco)
#> cigarette sugar nicotine nitrogen
#> Min. :1.400 Min. :12.58 Min. :1.240 Min. :1.720
#> 1st Qu.:1.550 1st Qu.:14.79 1st Qu.:1.870 1st Qu.:1.980
#> Median :1.680 Median :17.31 Median :2.160 Median :2.080
#> Mean :1.688 Mean :16.62 Mean :2.161 Mean :2.157
#> 3rd Qu.:1.780 3rd Qu.:18.55 3rd Qu.:2.430 3rd Qu.:2.210
#> Max. :2.090 Max. :20.05 Max. :3.280 Max. :2.870
#> chlorine potassium phosphorus calcium magnesium
#> Min. :0.740 Min. :1.64 Min. :0.42 Min. :2.790 Min. :0.780
#> 1st Qu.:2.150 1st Qu.:2.15 1st Qu.:0.48 1st Qu.:3.310 1st Qu.:0.860
#> Median :2.670 Median :2.22 Median :0.50 Median :3.560 Median :0.950
#> Mean :2.481 Mean :2.24 Mean :0.49 Mean :3.592 Mean :0.964
#> 3rd Qu.:2.840 3rd Qu.:2.40 3rd Qu.:0.51 3rd Qu.:3.720 3rd Qu.:1.040
#> Max. :3.300 Max. :2.64 Max. :0.56 Max. :4.570 Max. :1.250
# Correlation analysis
cor(tobacco)
#> cigarette sugar nicotine nitrogen chlorine
#> cigarette 1.0000000 -0.3198626 0.21555016 0.226000207 -0.62343918
#> sugar -0.3198626 1.0000000 -0.70199284 -0.705059364 0.42982387
#> nicotine 0.2155502 -0.7019928 1.00000000 0.768231725 -0.27053741
#> nitrogen 0.2260002 -0.7050594 0.76823172 1.000000000 -0.08936414
#> chlorine -0.6234392 0.4298239 -0.27053741 -0.089364140 1.00000000
#> potassium 0.4867307 0.1898693 -0.29428914 -0.007344682 -0.09292574
#> phosphorus -0.3204492 0.2438261 -0.04534413 -0.112258368 0.07383127
#> calcium -0.1212625 -0.4819467 0.68654613 0.627170771 0.13825072
#> magnesium -0.3134037 -0.5252157 0.73418610 0.604036129 0.11833719
#> potassium phosphorus calcium magnesium
#> cigarette 0.486730708 -0.32044919 -0.1212625 -0.3134037
#> sugar 0.189869253 0.24382615 -0.4819467 -0.5252157
#> nicotine -0.294289140 -0.04534413 0.6865461 0.7341861
#> nitrogen -0.007344682 -0.11225837 0.6271708 0.6040361
#> chlorine -0.092925739 0.07383127 0.1382507 0.1183372
#> potassium 1.000000000 -0.20542933 -0.5882255 -0.6108099
#> phosphorus -0.205429334 1.00000000 0.0138711 0.1549619
#> calcium -0.588225495 0.01387110 1.0000000 0.7638009
#> magnesium -0.610809895 0.15496189 0.7638009 1.0000000