ex1317: Dinosaur Extinctions-An Observational Study

In Sleuth2: Data Sets from Ramsey and Schafer's "Statistical Sleuth (2nd Ed)"

Description

About 65 million years ago, the dinosaurs suffered a mass extinction virtually overnight (in geologic time). Among many clues, one that all scientists regard as crucial is a layer of iridium-rich dust that was deposited over much of the earth at that time. The theory is that an event like a volcanic eruption or meteor impact caused a massive dust cloud that blanketed the earth for years killing off animals and their food sources. Dataset has Iridium depths by type of deposit.

Usage

ex1317

Format

A data frame with 28 observations on the following 3 variables.

Iridium

Iridium in samples (ppt)

Strata

a factor with levels "Limestone" and "Shale"

Depth

a factor with six levels: "1", "2", ..., "6"

Source

Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.

References

Alvarez, W. and Asaro, F. (1990). What Caused the Mass Extinction? An Extraterrestrial Impact, Scientific American 263(4): 76–84.

Courtillot, E. (1990). What Caused the Mass Extinction? A Volcanic Eruption. Scientific American 263(4): 85–92.

Examples

str(ex1317)

Example output

'data.frame':	28 obs. of  3 variables:
 $ Iridium: num  75 200 120 310 290 450 620 170 205 260 ...
 $ Strata : Factor w/ 2 levels "Limestone","Shale": 1 1 1 1 1 1 1 1 1 1 ...
 $ Depth  : Factor w/ 6 levels "1","2","3","4",..: 1 1 2 2 3 3 3 4 4 4 ...

Sleuth2 documentation built on May 2, 2019, 7:01 a.m.