How long it takes paint to dry can have an impact on the production capacity of a business. In May 2018, Deal’s Auto Body & Paint in Prescott, Arizona, invested in a paint­drying robot to speed up its process (The Daily Courier website,. An interesting question is Do all paint­drying robots have the same drying time? To test this, sup­ pose we sample five drying times for each of different brands of paint­drying robots. The time in minutes until the paint was dry enough for a second coat to be applied was recorded. The following data were obtained.
Robot 1: 128 137 135 124 141
Robot 2: 144 133 142 146 130
Robot 3 : 133 143 137 136 131
Robot 4: 150 142 135 140 153
At the a = .05 level of significance, test to see whether the mean drying time is the same for each brand of robot"