V Some researchers developing a new intelligence test are trying to decide the maximum time to allow for completion of the test. The researchers have recorded the times for completion of the test for 28 participants who took the test for practice. The histogram below summarizes the completion time information for these 28 participants. Frequency 10- 9 8. 6 6: 500 700 900 1100 1300 1500 Time for completion (in seconds) Based on the histogram, estimate the mean time for completion (in seconds) for the test takers in the sample. Carry your intermediate computations to at least four decimal places, and round your answer to at least one decimal place. X