Abstract:
The present era of consumerism has substantially redefined the relationship of
buyer and seller. Heightened consumer expectations have placed more
responsibility on the manufacturer for the performance of his goods and a
warranty or a written affirmation of the quality or performance of the product is
a requirement in most cases. However, little attention has been given by the
manufacturers for the scientific setting of warranty policies on computers. Thus
this paper explores a method to estimate warranty periods based on failure time
of computers. The data pool consists of two data sets, namely repair data and
sales data from a reputed IT solution company. For each computer, the
installation date is taken from sales data and failure data is taken from repair
data and the failure time is calculated. A weibull model was found to fit the data
well. Cumulative probabilities of failures based on this model were taken in to
account in calculating suitable warranty periods. Graphical goodness of fit
consisting of probability plots and simultaneous equal precision (EP) confidence
bands are used to assess the validity of distributional assumptions. The main
problem encountered in this study is setting suitable warranty periods. Life times
of the computers were used as the basic modelling variable. The process of
solving the problem consists of various statistical methods and techniques. Since
there are various engineering methods to calculate warranty periods, these
statistical methods show a different angle. To illustrate a valid warranty period
certain distributional assumptions were used and those assumptions laid a base
for solving the problem
