Possible Issue:
Slide and Audio/Transcription have different information which may cause confusion.
Video section starts at minute 7:40
In this slide the instructor notes that the observed statistic is -2.07, while the slide says otherwise (z=-1.336). The p-value seems to align with the slide and the audio/transcript though.
Which leads to another confusion: the instructor says that the p-value is smaller than the significance level(\alpha), when in fact it’s bigger (0.091 > 0.05). The decision on the slide seems correct though: fail to reject H_0 but the audio/transcript says otherwise (reject H_0).
Here is the transcript from that section:
You also consider a significance level of alpha equals 0.05. And as you just saw from the previous slides, if H0 is true, then the test statistic follows a Gaussian distribution with the data you have. This means that the observed statistic is negative 2.07. What is the p-value for the sample? Well, it will be the area under this Gaussian PDF which has a value of 0.091. Since this is smaller than the significance level, you can reject the null hypothesis and accept that as true, that the conversion rate of design B is bigger than the one for design A.
Is this truly an issue with the material, or is my understanding wrong? Please feel free to enlighten me 