Related Topics:

Nevada Chart Format

Example of a Nevada Chart Warranty Analysis

An electronics manufacturer wants to study the expected number of returns for a product they created using materials obtained from two suppliers. The sales and returns data for the product are collected and entered into a Nevada chart warranty analysis folio, as shown next.

This implies that the population is not homogeneous and that different subpopulations may exist in the data. One suspected reason for the deviation may be the type of material used by the suppliers. The manufacturer concludes that the data set needs to be analyzed based on their material supplier.

Click the Calculate icon to recalculate the parameters. The results show that for Supplier 1, the parameters are: beta = 2.3819 and eta = 25.3976; for Supplier 2, the parameters are: beta = 2.3207 and eta = 21.2829.

The resulting plot is shown next. As you can see, the two subsets do not overlap at the 90% confidence level. This confirms that the two data sets are significantly different at the 90% confidence level.

Return to the Sales or Returns data sheet. Choose Warranty > Tools > Generate Forecast or click the icon on the control panel.

The following figure shows the Forecast sheet with the warranty period starting in October 2010 and ending in January 2011. As you can see, the highest number of product returns is expected to come from the batch that was in-service in March.

Earlier, we found out that the material from Supplier 2 tends to have a higher probability of failure when compared to the material from Supplier 1. However, the current plot shows that Supplier 1 is expected to have a higher number of total returns within the specified warranty period. Looking back at the Sales sheet, we can see that the manufacturer sold three times more units made with materials from Supplier 1 compared to the number of sold units using materials from Supplier 2. Therefore, more units made with the materials from Supplier 1 will be returned each month due to the high sales volume of those units. This forecast analysis can help the manufacturer plan for warranty costs and service, as well as plan for the number of units to produce using materials from each supplier and decide whether it would be worthwhile to have Supplier 2 increase the reliability of its materials.

 

© 1992-2013. ReliaSoft Corporation. ALL RIGHTS RESERVED.