What is the simplified form of this expression?

What could explain what happened when the time was equal to 120 minutes

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

The measure of an angle is 117°. what is the measure of a supplementary angle?