Official 2020 AP Stats Exam College Board Lesson #4 Significance Tests for Means (SPDC) 4_9_2020

Hi All!

That was a great lesson from Brendan Murphy!  Here are my take-aways and teacher comments:

Brief Reminders:

• Lessons are here: https://www.youtube.com/watch?v=taxqJgjlEM0&list=PLoGgviqq4845u-QDW3bikMhC4uQsuYDpy&index=12

• Lessons: April 6-10: Units 6-7 taught first because many schools either didn’t get to these entirely or at all (we did get through most of this); April 13-May 1: Units 1-5
• AP Stats Exam Friday May 22 from 2-2:45 EST
• All resources available at Statsmedic.com/youtube
• If you need a device take the Exam go to cb.org/tech

Last night’s homework:

• This is a preview of how if 0 (zero) is in the interval we find support (DO NOT REJECT H₀) for the Null Hypothesis.

2012 Multiple Choice #27:

• H₀: M_A = M_{B  is the same as saying} H₀: M_A - M_B = 0  if you like this better because it reminds you more of the idea of that the null hypothesis is the statement of no difference (difference equals zero)
• He introduces the idea how matched pairs T-Tests have a “dependent feel” (usually before/after types) to them.  In this case you’d use a one sample T-Test on difference list (L₃).

Example 1 “Manual dexterity (before/after)” performing a 1 mean difference (L₃) significance test (4 step SPDC process) TPS section 9-3 (last example in you notes)

• The name of the procedure is what we call the Inference Method (IM) T-Test
• We remember the conditions by using the acronym Random Normal Independence (RNI)
• You can use ZoomStat to sketch the plot of a boxplot like we did in class instead of a manually drawn dot plot
• You can state something like we will assume that there are at least 120 in the population as your Independence step as we do in class
• You must report df = 11
• You can report all of the data from your calculator function Stat à Test  2: T-Test on L₃ in the Do step:  Notice that he clearly states that is what is needed 😊

Example 2 “Baby walkers” performing a 2 means significance test (4 step SPDC process) TPS section 10-2

• The name of the procedure is what we call the Inference Method (IM) 2 Samp T-Test
• We remember the conditions by using the acronym Random Normal Independence (RNI)
• You can state something like we will assume that there are at least 540 and 550 in the population for both walkers and nonwalkers as your Independence step as we do in class
• Since both n-values are greater than 30, you can state that the CLT implies normality
• You must report df = 102.83  from you calculator, see next bullet
• You can report all of the data from your calculator function Stat à Test  4: 2 Samp T-Test  in the Do step:  Notice that he clearly states that is what is needed 😊
• Part b) nicely reviews how experimental studies imply causation (not observational), a Chapter 4 topic 😊

If you can, do the homework on Type I/Type II Error (or watch the recoding at you leisure) and follow along as we learn.

As always please email me with questions, comments, thoughts.

Take care!