Wishes to know the mean number of words a third grader can read per minute. She wants to make an estimate at the 80%80% level of confidence. For a sample of 143143 third graders, the mean words per minute read was 25.125.1. Assume a population standard deviation of 33. Construct the confidence interval for the mean number of words a third grader can read per minute. Round your answers to one decimal place.

Write a polynomial function f of least degree that has rational coefficients, a leading coefficient of 1, and the given zeros. 1, 2−√3

Asmall (but heavy) particle placed in a glass of water will follow a zigzag motion because the particle will bounce off of the water molecules it meets. this is called brownian motion. a physicist simulates this on a computer, by varying the distance a particle can travel (called the mean free length), on average, before it collides with a water molecule and assigning the change in motion to be one of 8 directions, each with a similar probability. by running the simulated particle (with the same mean free length) many times she determines that it should take 15 seconds, on average, for the particle to fall to the bottom, with a standard deviation of 1.5 seconds. next she lets a real particle fall through a glass of water and finds that it took 18 seconds. what does she conclude, and why?

Can someone tell me if these are correct?