Could you please explain why the STD displayed in video as 1.49 instead of 1.22

1.49 is no S.dev it is the variance σ=1.22 σ2 = 1.49 The normal distribution is defined by mean and variance. For all those who don't get same result after substracting the s.dev, it is cause in the video he has previously ROUNDED, (not mentioned) the numbers, substracting decimal you only change the visualization of the number not its value.

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