


Hello Need help with this question please. I am not sure where the answer is 3.59%.
Thank you for taking a look in advance.
Cumulative ztable:
z 0.00 0.01 0.02 0.03
1.6 0.9452 0.9463 0.9474 0.9484
1.7 0.9554 0.9564 0.9573 0.9582
1.8 0.9641 0.9649 0.9656 0.9664
Monthly sales of hot water heaters are approximately normally distributed with a mean of 21 and a standard deviation of 5. What is the probability of selling 12 hot water heaters or less next month?
I picked 0.9641. i was wrong. it is 3.59% (Where did they calculate 3.59%)
Comments
You were close to getting this one.
Short version is you needed to do 10.9641 = 0.0359
96.41% represents the probabilty of selling 12 hot water heaters or MORE. The question calls for 12 or Less.
Always best to draw graphs on these to give yourself a visual.
OMG. 🤦♀️
I truly appreciate your help.