Answers for all ‘Test Yourself’ questions from the book to check your performance and widen your overall understanding of the contents.

1. z-scores represent the difference between a raw score and a sample mean in standard deviation units.  z-statistics represent the difference between a sample mean and a population mean in standard error units.  Both put the raw difference between two values into standardized units, but z-scores do so within a sample while z-statistics do so within the sample distribution.
2.  
   
   1. Yes, 26
   2. No
   3. No
3.  
   
   1. n = 18
   2. df = 17
   3. α = .01
   4. No, the researcher retained the null and did not find statistical significance.
   5. The sample mean and the population mean described by H₀ were 0.90 standard errors apart.
4.  
   
   1. Standardized
   2. Unstandardized
   3. Standardized
5.  
   
   1. -1.645
   2. ±2.145
   3. ±1.96