Viscosity for aircraft primer paint data

"The viscosity of an aircraft primer paint is an important quality characteristic. The product is produced in batches, and because each batch takes several hours to produce, the production rate is too slow to allow for rational subgroups of size greater than one." (Montgomery, 2005, p. 232)

data(viscosity)

Format

A data frame with 35 observations on the following 3 variables.

batch

batch number

viscosity

viscosity measure

trial

preliminary sample indicator (TRUE/FALSE)

References

Montgomery, D.C. (2005) Introduction to Statistical Quality Control, 5th ed, New York, John Wiley & Sons, pp. 232-235

Examples

data(viscosity)
describe(viscosity, by = trial)
#> ── trial = FALSE ─────────────────────────────────────────────────────────────── 
#>           Obs  Mean StdDev   Min Median  Max
#> batch      15 28.00 4.4721 21.00  28.00 35.0
#> viscosity  15 34.44 0.5736 33.27  34.55 35.4
#> 
#> ── trial = TRUE ──────────────────────────────────────────────────────────────── 
#>           Obs  Mean StdDev   Min Median   Max
#> batch      20 10.50 5.9161  1.00  10.50 20.00
#> viscosity  20 34.09 0.5694 33.27  34.03 35.96
plot(viscosity ~ batch, data = viscosity, type = "o", 
     pch = ifelse(trial, 19, 1))