A quality engineer for a camera manufacturer wants to shorten the flash recovery time. Flash recovery time is the least amount of time that is required between flashes. The engineer wants to determine whether a relationship exists between the voltage that remains in the camera battery immediately after a flash and the flash recovery time. The engineer also wants to determine whether there are differences in flash recovery time between old and new formulations of the battery. The engineer collects random samples of batteries made with the old and new formulations. The engineer measures the volts remaining immediately after a flash and the flash recovery time for each.
As part of the initial investigation, the engineer creates a scatterplot of volts after versus flash recovery time, grouped by battery formulation, to assess the relationship between the two variables for the two formulations.
Interpret the results
Minitab calculates a separate regression equation for each group. The regression lines suggest that, within the range of voltages tested, recovery times for the new formulation are generally faster than the recovery times for the old formulation. The regression lines and equations suggest a negative linear relationship between recovery time and voltage for both groups. On average, with an increase of 1 volt, recovery time of the new batteries is reduced by approximately 2.7 seconds. For the old formulation, the recovery time is reduced by approximately 3.9 seconds.
Flash Recovery = 8.04507 − 2.69921 Volts After
Flash Recovery = 10.6095 − 3.89908 Volts After