A student takes a 21- question, multiple-choice exam with four choices for each question and guesses on each question. Assume the variable is binomial.

Find the probability of guessing at least 10 out of 21 correctly.

What is the value of  y  in the solution to the system of equations? x  +  y  =  12x  –  3y  =  –30a. –8b. –3c. 3d. 8

High schoolmathematics 5 points keith is the leading goal scorer for a team in an ice hockey league. last season, he scored 42 goals in 82 games. assuming he scores goals at a constant rate, what is the slope of the line that represents this relationship if the number of games is along the x-axis and the number of goals is along the y-axis?

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.