these are all the information

1. A researcher in a certain manufacturing's cell battery wishes to compare four different devices on the lifetime of a cell battery. He would like to know if he can conclude that the four devices are in fact have different lifetime. He suspected that different brands of battery have an effect on the lifetime. After conducting an appropriate experiment, the following results are obtained. Brand's of battery Devices Total 1 2 3 1 71 72 72 215 68 67 68 203 3 74 75 74 223 4 67 67 67 201 Total 280 281 281 842 a) What is the most appropriate design for the above problem? State whether fixed or random effect models b) Based on this data, would the researcher manage to conclude his design objective. Justify your answer c) Estimate the effect of device 3 and interpret your result Verify the expression for the variability of the lifetime of the battery. Hence, estimate this variability. e) Test whether the variance of the error terms are equal? 1. A researcher in a certain manufacturing's cell battery wishes to compare four different devices on the lifetime of a cell battery. He would like to know if he can conclude that the four devices are in fact have different lifetime. He suspected that different brands of battery have an effect on the lifetime. After conducting an appropriate experiment, the following results are obtained. Brand's of battery Devices Total 1 2 3 1 71 72 72 215 68 67 68 203 3 74 75 74 223 4 67 67 67 201 Total 280 281 281 842 a) What is the most appropriate design for the above problem? State whether fixed or random effect models b) Based on this data, would the researcher manage to conclude his design objective. Justify your answer c) Estimate the effect of device 3 and interpret your result Verify the expression for the variability of the lifetime of the battery. Hence, estimate this variability. e) Test whether the variance of the error terms are equal