this is my question

1. The principal at Crest Middle School, which enrolls 500 sixth and seventh grade students, ls Interested In determining how much time students spend on homework each night. The table below shows the mean and standard deviation of the amount of time spent on homework each night [In minutes} for a random sample of 20 sixth-grade students and a separate sample of 20 seventh-grade students at this school. _- Standard Deviation sum-0mm --E_ -_E- Estimate the difference in mean times spent on homework for all sixth- and seventh grade students In this school us Ins a 90% condence interval