The lifetime of a 2 volt non-rechargeable battery has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. What is the z- score for batteries with lifetimes of 520 hours
Z = (score-mean)/SD
Insert values and calculate.
To find the z-score for a specific value in a normal distribution, you can use the formula:
z = (x - μ) / σ
Where:
z = z-score
x = value you want to find the z-score for (in this case, 520 hours)
μ = mean of the distribution (516 hours)
σ = standard deviation of the distribution (20 hours)
Now we can plug in the values into the formula and calculate the z-score:
z = (520 - 516) / 20
z = 4 / 20
z = 0.2
Therefore, the z-score for batteries with lifetimes of 520 hours is 0.2.