Question

The "Garbage Project" at the University of Arizona reports that the amount of paper discarded by households per week is normally distributed with mean 9.4 lb and standard deviation 4.2 lb. What percentage of households throw out at least 9 lb of paper a week? (Round your answer to one decimal place.)

Answer 1

To find the percentage of households that throw out at least 9 lb of paper per week, we need to calculate the z-score for this value.

Step-by-step explanation:

To find the percentage of households that throw out at least 9 lb of paper per week, we need to calculate the z-score for this value. The formula for the z-score is:

z = (x - μ) / σ

where x is the value we are interested in (9), μ is the mean (9.4), and σ is the standard deviation (4.2). Plugging in the values, we get:

z = (9 - 9.4) / 4.2 = -0.0952

We can then use a standard normal distribution table or a calculator to find the percentage of households above this z-score. This percentage gives us the answer to the question.