<image>A certain institution has $$200$$ employees, including young employees (20-35 years old), middle-aged employees (35-50 years old), and elderly employees (50 years old and above). The proportions of each group are shown in the pie chart. To understand the health status of the employees, Xiao Zhang, Xiao Wang, and Xiao Li each conducted a sample survey of the employees and organized the collected data into statistical tables, which are shown as Table $$1$$, Table $$2$$, and Table $$3$$.
Table $$1$$: Xiao Zhang's sample survey of the health indices of $$3$$ employees.
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Table $$2$$: Xiao Wang's sample survey of the health indices of $$10$$ employees.
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Table $$3$$: Xiao Li's sample survey of the health indices of $$10$$ employees.
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Based on the above materials, answer the following questions:
$$(1)$$ The central angle of the sector representing elderly employees in the pie chart is ______.
$$(2)$$ Among Xiao Zhang, Xiao Wang, and Xiao Li, ______'s sample survey data can better reflect the health status of the employees of the institution. Briefly explain the shortcomings of the sample surveys conducted by the other two.