STT 231 Lecture 9: STT 231 lecture 9-10

The relative frequency of a class is computed by

a. dividing the midpoint of the class by the sample size.
b. dividing the frequency of the class by the midpoint.
c. dividing the sample size by the frequency of class.
d. dividing the frequency of the class by the sample size.

A distribution has a standard deviation of σ=10. Find the z-score for each of the following locations in the distribution.

a. Above the mean by 5 points.

b. Above the mean by 2 points.

c. Below th mean by 20 points.

d. Below the mean by 15 points.

 Which of the following may be classified as shear-induced turbulence?

A. Turbulence caused by rotating ceiling fans.

B. Turbulence caused by fast-moving vehicles.

C. Turbulence caused by mountains and forests.

D. Turbulence caused when winds cross paths or change speed with altitude.

E. Turbulence caused by heat from the exhausts of airplanes.