Question 1178618
z=(x-mean)/sd
1. This would be z=500000/300000 or z> 5/3. That probability is 0.0478.
2. This would be -0.5< z < +0.5 or probability of 0.3829.
3. This would be z> (700,000)/300,000 or z > 7/3 The probability is 0.0098
4. The 91% percentile is from invnorm(0.91,0,1)=+1.34. This would be a sales level of 402,000 above the mean or 2,902,000. More exactly, it is 2,902,227.