Breakdown times of an insulating fluid under various levels of voltage stress

Data for Exercise 5.76

Fluid

Format

A data frame/tibble with 76 observations on two variables

kilovolts

a character variable showing kilowats

time

breakdown time (in minutes)

Source

E. Soofi, N. Ebrahimi, and M. Habibullah, 1995.

References

Kitchens, L. J. (2003) Basic Statistics and Data Analysis. Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning.

Examples

DF1 <- Fluid[Fluid$kilovolts == "34kV", ]
DF1
#> # A tibble: 19 × 2
#>    kilovolts  time
#>    <chr>     <dbl>
#>  1 34kV       0.19
#>  2 34kV       0.78
#>  3 34kV       0.96
#>  4 34kV       1.31
#>  5 34kV       2.78
#>  6 34kV       3.16
#>  7 34kV       4.15
#>  8 34kV       4.67
#>  9 34kV       4.85
#> 10 34kV       6.5 
#> 11 34kV       7.35
#> 12 34kV       8.01
#> 13 34kV       8.27
#> 14 34kV      12.1 
#> 15 34kV      31.8 
#> 16 34kV      32.5 
#> 17 34kV      33.9 
#> 18 34kV      36.7 
#> 19 34kV      72.9 
# OR
DF2 <- subset(Fluid, subset = kilovolts == "34kV")
DF2
#> # A tibble: 19 × 2
#>    kilovolts  time
#>    <chr>     <dbl>
#>  1 34kV       0.19
#>  2 34kV       0.78
#>  3 34kV       0.96
#>  4 34kV       1.31
#>  5 34kV       2.78
#>  6 34kV       3.16
#>  7 34kV       4.15
#>  8 34kV       4.67
#>  9 34kV       4.85
#> 10 34kV       6.5 
#> 11 34kV       7.35
#> 12 34kV       8.01
#> 13 34kV       8.27
#> 14 34kV      12.1 
#> 15 34kV      31.8 
#> 16 34kV      32.5 
#> 17 34kV      33.9 
#> 18 34kV      36.7 
#> 19 34kV      72.9 
stem(DF2$time)
#> 
#>   The decimal point is 1 digit(s) to the right of the |
#> 
#>   0 | 01113345577882
#>   2 | 2347
#>   4 | 
#>   6 | 3
#> 
SIGN.test(DF2$time)
#> 
#> 	One-sample Sign-Test
#> 
#> data:  DF2$time
#> s = 19, p-value = 3.815e-06
#> alternative hypothesis: true median is not equal to 0
#> 95 percent confidence interval:
#>   3.043765 18.082824
#> sample estimates:
#> median of x 
#>         6.5 
#> 
#> Achieved and Interpolated Confidence Intervals: 
#> 
#>                   Conf.Level L.E.pt  U.E.pt
#> Lower Achieved CI     0.9364 3.1600 12.0600
#> Interpolated CI       0.9500 3.0438 18.0828
#> Upper Achieved CI     0.9808 2.7800 31.7500
#> 
if (FALSE) {
library(dplyr)
DF3 <- dplyr::filter(Fluid, kilovolts == "34kV") 
DF3
}