Aconcrete mix is designed to withstand 3000 pounds per square inch (psi) of pressure. the following data represent the strength of nine randomly selected casts (in psi). 3970, 4100, 3100, 3200, 2950, 3830, 4100, 4050, 3460 compute the mean, median and mode strength of the concrete (in psi). compute the mean strength of the concrete. select the correct choice below and, if necessary, fill in the answer box to complete your choice. a. the mean strength of the concrete is nothing psi of pressure. (round to the nearest tenth as needed.) b. the mean does not exist.