Answer: 9.2 years
Step-by-step explanation:
Given the following :
Mean(m) = 11.7 years
Standard deviation (s) = 1.2 years
Recall the z-score formula :
Z = (x - m) / s
We can find the z-score by locating the value of 2% in the negative z-table, then solve for x.
2% = 0.02
0.02 falls most closely to 0.02018whuch is under - 2.05.
Using the z-score value in the formula above :
-2.05 = (x - 11.7) / 1.2
Cross multiply
(-2.05 × 1.2) = x - 11.7
-2.46 = x - 11.7
x = - 2.46 + 11.7
x = 9.24 years
