Write the null and alternative hypotheses in words and$/$or symbols for each of the following situations. If written in symbols, please define the symbols used.

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 firm are worried about the effect 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.