Statistics ,

in a table of random digits, each digit is to occur with a probability of 0.1.
a) a student examines a list of 200 random digits and counts only eleven 4s and thus claims that the table is not really random. explain the error in the student's thinking.
b) how many 7s would you expect to find in a random digit table consisting of 1,000 digits?

i think b) might be 100 because it says the probability of every number is 0.1, which is 10%, and 10% of 1,000 is 100. can someone and explain both of these? so !

Alex drew a circle with right triangle prq inscribed in it, as shown below: the figure shows a circle with points p, q, and r on it forming an inscribed triangle. side pq is a chord through the center and angle r is a right angle. arc qr measures 80 degrees.

In one day there are too high tides into low tides and equally spaced intervals the high tide is observed to be 6 feet above the average sea level after six hours passed a low tide occurs at 6 feet below the average sea level in this task you will model this occurrence using a trigonometric function by using x as a measurement of time assume the first high tide occurs at x=0. a. what are the independent and dependent variables? b. determine these key features of the function that models the tide: 1.amplitude 2.period 3.frequency 4.midline 5.vertical shift 6.phase shift c. create a trigonometric function that models the ocean tide for a period of 12 hours. d.what is the height of the tide after 93 hours?

Type the correct answer in the box. consider the system of linear equations below. rewrite one of the two equations above in the form ax + by = c, where a, b, and c are constants, so that the sum of the new equation and the unchanged equation from the original system results in an equation in one variable.