Using a 5 step procedure Suppose that the mean time spent on

Using a 5 step procedure

  Suppose that the mean time spent on Facebook is 19.5 minutes. A study of 100 visits shows a sample mean of 21.5 minutes and a sample standard deviation of 12 minutes.. Use a = 0.05 to test whether the mean time spent on Facebook has increased.

Solution

t= (21.5-19.5)/12/sqrt100= 1.67

Critical value from t table (df 100-1=99) is 1.66 <.1.67. so yes, mean time has increased.