1. Refer to the PSPP Analysis of Job Loss (BLI, 2015). You performed a one-sample t-test to test whether mean job loss percentages differ from 10. Suppose that the researchers tested whether job loss was less than 10 percent.   

Would the value of the observed test statistic be different than the one printed on the PSPP output? Answer Yes or No. Justify your answer.

 

 

 

Would the p-value of the observed test statistic be different than the one printed on the PSPP output? 

• Answer Yes or No. Justify your answer.
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Researchers took a random sample of 20 British citizens and used the Crime Survey for England and Wales (CSEW) to determine people’s trust level with the British police force. The study found that the trust level had a mean of 13.5 and a standard deviation of 4.3. The distribution of British people’s indication of their trust level with the police force was approximately bell-shaped and symmetric. 

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•  What is the 95% Confidence Interval for the population's mean trust level? Interpret this confidence interval in the words of this problem.  
• Researchers claim that the true population means trust level of British citizens with the police force differs from 15. Carry out a significance test to investigate the researcher’s claim.  
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  •  State the null and alternative hypothesis using statistical symbols. 
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  • The null hypothesis is the current belief:  : 
  • In our example it would have a form: :  
  • The Alternative hypothesis is what the researcher(s) [you] want to prove: : 
  • In our example it would have a form: :  
  • This means, we have a two-sided test: either  or 
  •  Find the value of observed test statistic using the formula:  
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  •  Find the p-value of the observed test statistic. You need to use the t -table.  
  • Do you reject Ho:  = 15 or fail to reject Ho? Justify your decision. 
  •  What conclusion (e.g., a directional conclusion), if any, can be made based on your decision in part iv.? 
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