Lesson 8.3 – Testing a Claim about a Proportion

  • Check the Random and Large Counts conditions for performing a significance test about a population proportion.  
  • Calculate the standardized test statistic for a significance test about a population proportion.  
  • Find the P-value for a one-sided significance test about a population proportion using Table A or technology.


Activity: Are you sure Mrs Gallas isn’t a good free throw shooter? 

Today we will move from simulations to calculating exact P-values.  In lesson 8.1, Mrs. Gallas claimed to be an 80% free throw shooter, but when she actually shot free throws she only made 32/50 free throws.  Every class conducted a simulation to see if she was lying.  Most classes concluded that she was lying (but not all of them), and each class found a different P-value.  How can we be more consistent with our results? Exactly how likely is it that an 80% free thrower shooter makes 32 out of 50 free throws?  Go through this recap and introduction with students and then have them work through the entire activity in their groups.  They have all the tools they need to complete this without teacher input.  We are simply putting together pieces that we’ve been using all year.  We encouraged ours to use their formula sheets from chapter 6.  That will help them to calculate the mean and standard deviation.  Make sure that students are using the null value.


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