5.13 Identify hypotheses, Part I. Write the null and alternative hypotheses in words and then symbols for

each of the following situations.

(a) A tutoring company would like to understand if most students tend to improve their grades (or not)

after they use their services. They sample 200 of the students who used their service in the past year

and ask them if their grades have improved or declined from the previous year.

(b) Employers at a rm are worried about the eect of March Madness, a basketball championship held each

spring in the US, on employee productivity. They estimate that on a regular business day employees

spend on average 15 minutes of company time checking personal email, making personal phone calls,

etc. They also collect data on how much company time employees spend on such non-business activities

during March Madness. They want to determine if these data provide convincing evidence that employee

productivity changed during March Madness.