AliCivil questions

• Random sample from a data frame in R
• Matching vector values by records in a data frame in R
• Change Date print format from yyyy-mm-dd to dd-mm-yyyy
• Chi-squared goodness of fit test in R
• Find the max date in a single column across multiple rows
• R saving the output of table() into a data frame
• Convert hour:minute:second (HH:MM:SS) string to proper time class

AliCivil answers