Area Under Curve Probability

3. The mean time for a group of runners on the 200 meter dash was 27 seconds with a standard deviation of 1.2. What percent of runners had a time that was less than 25.8 seconds?

• 47.5%

• 15.87%

• 68%

• 83.85%

A z-score tells you...

• the standard deviation of a sampling distribution.
• the original raw score on which it is based.
• if the distribution it comes from is normal.
• how many standard deviations away from the mean a score lies.

Find the area under the standard normal curve to the right of z = -2.67.

• 0.0869
• 0.9962
• 0.0008
• 0.1234

Find the area under the normal distribution curve between a z=-1.26 and z=.57. 

• 0.0047
• 0.9204
• 0.6119
• 0.4981

The average waist size for teenage males is 29 inches with a standard deviation of 1.4 inch. 
If waist sizes are normally distributed, estimate the proportion of teenagers who will have waist   sizes greater than 31 inches?

• 92.4%
• 10.5%
• 16%
• 7.6%

Find the area under the normal distribution curve to the left of 
Z=0.27.

• 0.3936
• 0.3897
• 0.6064
• 0.4892

Find the area under the normal distribution curve that represents the area to the left of Z =-2.37.

• 0.0089
• 0.9910
• 0.1401
• 0.1381

Find the area under the normal distribution curve between 
z=-1.53 and z=0.

• 0.437
• 0.563
• 0.500
• 0.063