Historical records over the past 10 years indicate that 30 percent of the major surgery patients are dissatisfied with their after-surgery care in the hospital. An analyst conducted a scientific poll based on 400 hospital patients and found that 64 were dissatisfied with their after-surgery care. Find the standard deviation of the sampling distribution of the sample proportion. Use Excel to find probabilities and values. Do not round intermediate calculations. Round final answer to four decimals: 0.0000