51/2% as a fraction in simplest form

What situation is an example of an observational study

Aproduction manager test 10 toothbrushes and finds that their mean lifetime is 450 hours. she then design sales package of this type of toothbrush. it states that the customers can expect the toothbrush to last approximately 460 hours. this is an example of what phase of inferential statistics

Tim earns $120 plus $30 for each lawn he mows. write an iniqualityvto represent how many lawns he needs to mow to make more than $310