Assume that a population of thousands of people whose responses were used to develop an anxiety test had scores that were normally distributed with M = 30 and s = 10.

  1. Assume that a population of thousands of people whose responses were used to develop an

anxiety test had scores that were normally distributed with M = 30 and s = 10. What

proportion of people in this population would have anxiety scores within each of the following

ranges of scores?

  • Below 20.
  • Above 30.
  • Between 10 and 50.
  1. What is SEM? What does the value of SEM tell you about the typical magnitude of sampling

 

     error?

  • As s increases, how does the size of SEM change (assuming that N stays the same)?

 

  • As N increases, how does the size of SEM change (assuming that s stays the same)?

 

  1. Under what circumstances should a t distribution be used rather than the normal distribution

to look up areas or probabilities associated with distances from the mean?