7th grade math help me pleasee

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?

Create a graph for the demand for starfish using the following data table: quantity/price of starfish quantity (x axis) of starfish in dozens price (y axis) of starfish per dozen 0 8 2 6 3 5 5 2 7 1 9 0 is the relationship between the price of starfish and the quantity demanded inverse or direct? why? how many dozens of starfish are demanded at a price of five? calculate the slope of the line between the prices of 6 (quantity of 2) and 1 (quantity of 7) per dozen. describe the line when there is a direct relationship between price and quantity.

Astock has a 25% probability of increasing by $10 and a 75% probability of decreasing by $5. what is the stocks expected increase or decrease?