We believe playing games on your cellphone can improve spatial reasoning. The mean number of items correct on a spatial reasoning task is 3.60. A sample of 10 people play cellphone games for 2 months. The 10 people who played cellphone games get an average of 4.20 items correct on the spatial reasoning task (S = 2.20) . Does playing games on your cellphone improve spatial reasoning? Complete the following and use an alpha of .05. We will use a t rather than a z here because we do not know the population SD . Step 1: Null: Playing games on your cellphone does not improve spatial reasoning. 3.60 Research: Playing games on your cellphone improves spatial reasoning. > 3.60