mistat (version 0.999)

VENDOR: Number of cycles required until latch failure

Description

Number of cycles reqiored until latch failure in 30 floppy disk drives from three different disk vendors.

Usage

data(VENDOR)

source

Kenett, R. and Zacks, S. (1998) Modern Industrial Statistics: The Design and Control of Quality and Reliability. Duxbury Press.

Details

Three different vendors are considered for supplying cases for floppy disk drives. The question is whether the latch mechanism that opens and closes the disk loading slot is sufficiently reliable. In order to test the reliability of this latch, three independent samples of cases, each of size $n = 10$, were randomly selected from the production lots of these vendors. The testing was performed on a special apparatus that opens and closes a latch, until it breaks. The number of cycles required until latch failure was recorded. In order to avoid uncontrollable environmental factors to bias the results, the order of testing of cases of different vendors was completely randomized. In data VENDOR there are the results of this experiment, arranged in 3 columns. Column 1 represents the sample from vendor $A_1$; column 2 that of vendor $A_2$ and column 3 of vendor $A_3$.

Examples

data(VENDOR)

VENDOR <- stack(VENDOR)               
                                      
VENDOR$ind <- as.factor(VENDOR$ind)   
                                      
VENDOR$values <- sqrt(VENDOR$values)  
                                              
confint(lm(values ~ -1 + ind,         
           data=VENDOR))