Can someone answer this ? a circle has a circumference of 1pi what is the diameter if the circle

In an experiment you are to flip a two sided coin 100 times and record 55 heads up and 45 tails up determine the theoretical and experimental probability of getting a heads up in the experiment.

Which expression is equivalent to (4x^3*y^5)(3x^5*y)^2 \a) 24x^13*y^7b) 36x^13*y^7c) 36x^28*y^7d) 144x^16*y^12

The head librarian at the library of congress has asked her assistant for an interval estimate of the mean number of books checked out each day. the assistant provides the following interval estimate: from 740 to 920 books per day. what is an efficient, unbiased point estimate of the number of books checked out each day at the library of congress?