Sophia Intro to Stats Unit 4 Milestone 4

Sophia Intro to Stats Unit 4 Milestone 4.For ten students, a teacher records the following scores of two assessments, Quiz 1 and Test. Quiz 1 (x) Test (y) Mean 11.9 14.3 Standard Deviation 3.3 3.5 The correlation of Quiz 1 and Test is 0.568. Given the information below, what is the slope and y-intercept for the least-squares line of the Quiz 1 scores and Test scores? Answer choices are rounded to the hundredths place. Slope = 0.54 y-intercept = 1.71 Slope = 0.54 y-intercept = 1.22 Slope = 0.60 y-intercept = 7.16 Slope = 0.60 y-intercept = 1.22 RATIONALE We first want to get the slope. We can use the formula: To then get the intercept, we can solve for the y-intercept by using the following formula: We know the slope, , and we can use the mean of x and the mean of y for the variables and to solve for the y-intercept, . CONCEPT Finding the Least-Squares Line 2 A bank manager declares, with help of a scatterplot, that the number of health insurances sold may have some association with the number of inches it snows. How many policies were sold when it snowed 2 to 4 inches? RATIONALE In order to find the total number of policies between 2 and 4 inches, we must add the three values of 10 in that interval. At 2 inches, there were 100 policies. At 3 inches, there were 110 policies. At 4 inches, there were 140 policies. So the total is 100 + 110 + 140 = 350 policies. CONCEPT Scatterplot 3 Which of the following scatterplots shows an outlier in the y-direction?