As people age daily stress and worry decrease and happiness increases according to an analysis of 340 847 adults ages 18 to 85 in a certain country The graphs show a portion of the research Complete parts a and b below Percentage Reporting Stress 60 50 40 30 20 10 22 Age 62 Percentage Reporting Stress A 60 50 40 30 20 10 0 of 1 22 36 62 22 15 30 45 60 75 Age a Find the slope of the line passing through the two points shown in the line graph Express the slope as a decimal Round to one decimal place as needed b Use the answer from part a to complete the statement For each year of aging the percentage of Americans reporting a lot of stress decreases by The rate of change is value of m year of aging age group percentage of stre per year of aging