Posted by mk. on Friday, April 26, 2013 at 5:30am.
The manager of a local gym has determined that the length of time members spend at the gym is a normally distributed variable with a mean of 80 minutes and a standard deviation of 20 minutes.
What proportion of members spend less than 55 minutes at the gym? Use the standard normal distribution tables of your Wegner textbook. Give your answer to the nearest percentage, e.g. 54% or 28% (remember to include the % sign!!!).
(Based on Wegner, Exercise 19, p149, 3rd ed / Exercise 8.17, p208, 2nd ed)

statistics  mk., Friday, April 26, 2013 at 5:34am
The manager of a local gym has determined that the length of time members spend at the gym is a normally distributed variable with a mean of 80 minutes and a standard deviation of 20 minutes.
What proportion of members spend less than 55 minutes at the gym? 
statistics  PsyDAG, Friday, April 26, 2013 at 2:01pm
Z = (scoremean)/SD
Find table in the back of your statistics text (Wegner?) labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score. Multiply by 100. 
statistics  Siviwe, Friday, April 17, 2015 at 9:29am
75