Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms.
A. 45% of the student weights are above ____ kilograms?
Z=.3264=x-75.5/10.3 Now what? I am lost! Please help me!
Thanks!
To find the weight above a certain value, you need to use the standard normal distribution table or a calculator.
1. Convert the percentage into the corresponding z-score from the standard normal distribution table. For example, for 45%, if you refer to the table, you'll find that the corresponding z-score is approximately 0.1257.
2. Use the z-score formula to find the weight above a certain value:
z = (x - μ) / σ
In this case, you already have the z-score (0.1257), the mean (μ = 75.5 kg), and the standard deviation (σ = 10.3 kg). Rearranging the formula, you can solve for x (the weight you need to find):
x = μ + (z * σ)
Plugging in the values:
x = 75.5 + (0.1257 * 10.3)
x ≈ 75.5 + 1.2759
x ≈ 76.7769
Therefore, approximately 45% of the student weights are above 76.78 kilograms.