1. Giventhatzisthestandardnormalvariable(withmean0andstandarddeviation1),find
a. P(-1.25<z<2.55) b.P(1.03<z<2.33) 

2. Given that IQ scores are normally distributed with = 100 and = 15 , find probability that individual will have an IQ level: 

a. between 68 and 120 b. Above 90 c. below110

3. Theserumcholesterollevelsformeninoneagegrouparenormallydistributedwithamean of 178.1 and a standard deviation of 40.4. All units are in mg/100 mL. Find the two levels that separate the top 9% and the bottom 9%.