I coded in R as first 2 pictures and I faced with an error which is at 3rd picture. How can I fix this error?

271 - for (i in 1:nrow(hospitals_table)) \{ 272 t.test_result [2] t.test_result\$conf.int [1] Error in 'summarize()': ! Problem while computing 'mean = mean(management_score)'. i The error occurred in group 1 : country = "Canada". Caused by error in 'mean() : ! object 'management_score' not found Backtrace: 1. data %>% group_by(country) %>% 10. base: : mean(management_score) > |