Quiz 07 Normal Curves 7.3 • Name:

1. For the following curves A, B, and C determine the mean and the standard deviation σ:
three normal curves
normal (3K)

CurveMean standard deviation σ
A  
B  
C  

2. Pohnpei Islands Central High School students had a mean of 10.9 and a standard deviation σ of 5.0 on the high school level questions on the mathematics entrance test March 2005. Assume the distribution is normal for these problems.

  1. __________ What is the probability a student scored below 5.9 on the mathematics entrance test?
  2. __________ An 18 is a mininum pass of the mathematics entrance test. What percent of PICS students scored above 18? Hint: This one will require use of Excel.
  3. __________ If 505 students took the mathematics entrance test at PICS, what number of students passed with a score above 18?
  4. The probability calculated in question 2a above is the probability a student scored randomly on the mathematics entrance test. What does it mean that these students scored no better than random?

Normal Statistics
Calculate a z value from an x z = standardize.gif (905 bytes) =STANDARDIZE(x, , σ)
Calculate an x value from a z x = σ z + =σ*z+
Find a probability p from a z value =NORMSDIST(z)