I need help on both of those 4 problems

According to the normal model, what percent of receivers would you expect to gain fewer yards than 2 standard deviations below the mean number of yards

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angles. measure need asap

Which of the following best describes the graph below? + + 2 + 3 + 4 1 o a. it is not a function. o b. it is a one-to-one function. o c. it is a many-to-one function. o d. it is a function, but it is not one-to-one.