Throughout the worlds, natural ocean beaches are beautiful sights to see. If you have visited natural beaches, you may have noticed that when the gradient or drop off is steep, the grains of sand tend to be larger. In fact, a man made beach with "wrong" size of granules of sand tend to be washed away and eventually replaced when the proper size grain is selected by the action of the ocean and the gradient of the bottom. Since man made beaches are expensive, grain size is an important consideration.

Use the data set with

x = median diameter of granules of sand

y = gradient of beach slope in degrees on natural ocean beaches.

a) Calcule the pearson correlation and create a scatterplot and explain it.

b) Create the lineal regression model.

c) Explain the R-square

d) Use the residual analysis to check the model.

e) If we have a truck of sand of .38mm. What is the slope tha the model predict?