I have data panel. I try to calculate the

1. Variable "

2. Variable "

Question:

1. How to calculate average change in cash ratios for all industries as a

would appreciate any help

many thanks

**average change**in variable "*"***cashratio**1. Variable "

**", consist of: construction, manufacturing and retail trade;***SIC*2. Variable "

*" : the time range is from 2004 to 2014;***Year**Question:

1. How to calculate average change in cash ratios for all industries as a

**whole (SIC)**and for each industry (construction, manufacturing and retail trade) over time (2004 to 2014)would appreciate any help

many thanks

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