Question

What is the z-score for a light bulb with a life expectancy of 2085 hours if the mean is 2000 hours and the standard deviation is 50 hours?

a) 1.7
b) 1.6
c) 0.7
d) 0.5

Answer 1

The z-score for a light bulb with a life expectancy of 2085 hours, given a mean of 2000 hours and a standard deviation of 50 hours, is 1.7.

Step-by-step explanation:

To calculate the z-score for a light bulb with a life expectancy of 2085 hours, where the mean is 2000 hours and the standard deviation is 50 hours, we use the following formula:

Z = (X - μ) / σ

Where:
X = value to be standardized (2085 hours)
μ = mean value (2000 hours)
σ = standard deviation (50 hours).

Plugging in the values we get:
Z = (2085 - 2000) / 50
Z = 85 / 50
Z = 1.7.

Therefore, the z-score for a light bulb with a life expectancy of 2085 hours is 1.7.