3 points Civil engineers often use the straight-line equation, y = bo + b 1x, to model the relationship between the shear strength y of masonry joints and precompression stress, x. To test this theory, a series of stress tests were performed on solid bricks arranged in triplets and joined with mortar. The precompression stress was varied for each triplet and the ultimate shear load just before failure (called the shear strength) was recorded. The stress results for n = 7 resulted in a Coefficient of Determination of 0.8436. Given that r 2= 0.8436, give a practical interpretation of r 2, the coefficient of determination for the least squares model. O About 84.36% of the total variation in the sample of y-values can be explained by (or attributed to) the linear relationship between shear strength and precompression stress. O In repeated sampling, approximately 84.36% of all similarly constructed regression lines will accurately predict shear strength. O We expect to predict the shear strength of a triplet test to within about 0.8436 tons of its true value. We expect about 84.36% of the observed shear strength values to lie on the least squares line. Next3 points An urn contains 7 red and 13 green balls. Two balls are drawn with replacement (i.e. the draws are independent of each other). Determine the probability that one ball of each color is drawn in any order. O 0.4550 O 0.2275 O 0.5450 O 0.87753 points Determine the sample standard deviation,s, for the following set of sample data. Hint: x =24 X (x-x ) ( X- x ) 2 18 22 24 32 O 5.10 5.89 O 26.0 O 34.67A runner tracks their performance by recording race information in a journal. The journal contains the event name, the race in kilometers and the time of completion. Classify each variable as qualitative or quantitative. A sample data tabl below. Event length completion of race (km) time (minutes) labor day 5 32.7 octoberfest 10 72.2 half-marathon 21.1 185.8 Event - qualitative; length of race - quantitative; completion time - qualitative Event - quantitative; length of race - quantitative; completion time - qualitative Event - qualitative; length of race - quantitative; completion time - quantitative O Event - qualitative; length of race - qualitative; completion time - quantitative