All 4 parts are from save graph from the top

3. In a mountain region there appears to be a relationship between the number of trees growing in the region and the depth of snow in winter. A set of 10 areas was chosen, and in each area the number of trees was counted and the depth of snow measured. The results are given in the table below. Number of trees (x) Depth of snow in cm () 45 30 75 50 66 40 27 25 44 30 28 60 35 35 20 73 47 25 (a) Use your graphic display calculator to find (i) the mean number of trees; (ii) the standard deviation of the number of trees; (iii) the mean depth of snow; (iv) the standard deviation of the depth of snow. (4) (b) Write down the product-moment correlation coefficient, r. (2) (c) Write down the equation of the regression line of y on x. (2) (d) If the number of trees in an area is 55, estimate the depth of snow. (2)