In a certain neighborhood, the average number of candies received while trick-or-treating is 50, with a standard deviation of 12. If Isaac received 40 candies, calculate his z-score to the nearest thousandth.
A. 0.833
B. 0 point 8 3 3
C. −0.833
D. negative 0 point 8 3 3
To calculate the z-score, we use the formula:
z = (X - μ) / σ
Where:
X = the individual value (number of candies received by Isaac) = 40
μ = the mean = 50
σ = the standard deviation = 12
Plugging in the values:
z = (40 - 50) / 12
z = -10 / 12
z = -0.833333333333...
Rounded to the nearest thousandth, Isaac's z-score is:
z ≈ -0.833
C. -0.833.