Authors
Kevin Potcner
JMP
Objective
Evaluate the durability of mobile phone screens in a drop test. Determine if a desired level of durability is achieved for each of two types of screens and compare performance.
Background
The durability of a product is clearly an important quality characteristic for both the end user and the manufacturer. For end users, durability is especially important for mobile phones. Dropping a phone on a hard surface, for example, can result in the screen cracking or even breaking, rendering the phone unusable. To evaluate the durability of these screens, manufacturers subject a sample of screens to a variety of tests to simulate typical wear and tear by a user, such as dropping the phone onto a concrete surface.
Material scientists for a screen manufacturer have been experimenting with two new formulations of an aluminosilicate glass. These two formulations were produced by making modifications to the material components and the curing process. For simplicity, we will refer to these two formulations as Screen Types A and B.
A sample of 10 screens of each type was developed for testing. Each screen was installed into the same style of phone. The phones were then dropped in a controlled identical manner from a height of 1 meter onto a concrete surface. A binary variable “Success” (no damage) and “Fail” (screen damage) was recorded.
One of the company’s goals is that 97% of the screens manufactured would be able to experience a drop of 1 meter without becoming damaged (i.e., the Population Success Rate)
The Task
There are two primary questions the engineering team is hoping the data can address:
- 1. Is there enough statistical evidence to conclude that the Population Success Rate at a 1.0m Drop Height for each of the Screen Types is at least 97%?
- 2. Is there statistical evidence to conclude that the Population Success Rate for one of the Screen Types is better than the other?