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Ornithologists, scientists who study birds, tag sparrow hawks in 13 different colonies to (b) Explain in words what the slope and y-intercept of the regression line tell us. study their population. They gather data for the percent of new sparrow hawks in each colony and the percent of those that have returned from migration. Round your answer to two decimal places. Percent return: 78; 66; 81; 52; 73; 63, 52; 44; 63; 44; 60; 46; 38 The slope of the least squares line is Number For each percentage increase in returning birds, the percentage of new birds in the colony Click for List by Increase or Percent new: 6; 5; 8; 12; 12, 15; 16; 17; 18; 18; 15; 20, 20 Number Decrease Enter the data into your calculator and make a scatter plot. Use your calculator's regression The y-intercept of the least squares line is Number . When there are no returning function to find the equation of the least-squares regression line. Add this to your scatter sparrow hawks, there will be almost Number new sparrow hawks. plot. (a) What is the equation of the least-squares regression line? Use a to represent percent return. (c) How well does the regression line fit the data? Explain your response. Round any calculated values to two decimal places. Round your answer to two decimal places y = The coefficient of determination indicates that Number % of the variation in the percent of new birds is explained by the model. The correlation coefficient, r = sin(a) 20 indicates a fairly Click for List * correlation between returning and new percentages. Strong or Weak (d) An ecologist wants to predict how many birds will join another colony of sparrow hawks to which 66% of the adults from the previous year have returned. What is the prediction? Round your answer to the nearest integer The predicted percent of new birds is |Number %. A music school has budgeted to purchase three musical instruments. They plan to purchase a piano costing $2,000, a guitar costing $600, and a drum set costing $675. The mean cost for a piano is $4,000 with a standard deviation of $2,500. The mean cost for a guitar is $500 with a standard deviation of $200. The mean cost for drums is $700 with a standard deviation of $100. Which cost is the lowest, when compared to other instruments of the same type? Which cost is the highest, when compared to other instruments of the same type? Justify your answer. Piano, guitar, or Highest or drums The Click for List has the lowest cost when compared to other instruments of the Lowest same type since it has the Click for List z-score of Number Piano, guitar, or Highest or drums Lowest The Click for List has the highest cost when compared to other instruments of the same type since it has the Click for List z-score of Number Three students were applying to the same graduate school. They came from schools with different grading systems. Which student had the best GPA when compared to other students at his school? Student| GPA School Average GPA | School Standard Deviation O Thuy Thuy 3.3 2. 0.8 O Vichet Vichet 84 78 20 O Kamala Kamala 8 8.3 0.5 One hundred teachers attended a seminar on mathematical problem solving. The attitudes (b) What is the standard deviation for this sample? of a representative sample of 12 of the teachers were measured before and after the seminar. A positive number for change in attitude indicates that a teacher's attitude toward Round your answer to two decimal places. math became more positive. The 12 change scores are as follows: = Number 2; 6; -1; 2; 0; 5; -2; 1; -1; 6; 3; -2 (a) What is the mean change score? (d) Find the change score that is 2.2 standard deviations below the mea Round your answer to two decimal places. (c) What is the median change score? Round your answer to two decimal places. r = Number Number Number
