help

1 That's exactly what you'tl get if you use summarize() to apply mean(size) to the grouped data in I by_packoge: Give it a shot. 25% summarize(mean(stze)) Error: object 'size' not found >mean(size) Error: object 'stze' not found > by_package x " is missing, with no default > by_package s- sumarize(mean(size.)