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

This is an example of Probability based inference.

Statistical inference is the process of using data analysis to deduce properties of an underlying probability distribution.

Inferential statistics makes inferences and predictions about a population based on a sample of data taken from the population in question.

can you add an image ?

step-by-step explanation:

the answer would be 1 1/72

step-by-step explanation:

you can rewrite the equation by separating the parts and then solving individually:

10-9=1

1/8 - 1/9=

find l c d and then combine:

1 1/72