Standard Deviation and Variance (with the TI-Nspire) | IB Maths AI SL Statistics

The fifth video in my IB Maths AI SL statistics series. Two sprinters have the same mean and the same range. So who is more consistent? This is where standard deviation comes in. We look at what standard deviation actually tells you, how to find it on the TI-Nspire from a list and from a frequency table, and why you must use σx and not sx. Then variance, and what happens to the mean, standard deviation and variance when you add to or multiply every value. You don't need the formula for AI SL. The GDC does the work, so focus on what the number means. There are pause questions all the way through and an exam-style question at the end. Have your GDC and notebook ready. Previous video: Frequency Tables and Grouped Data Chapters 0:00 Intro 0:54 Two sprinters: who is more consistent? 1:33 Same mean, same range. So are they the same? 3:27 What standard deviation means 5:35 Standard deviation on the TI-Nspire 8:41 σx or sx? Don't lose the mark 9:13 Your turn: quiz scores 11:04 Variance 12:48 Standard deviation from a frequency table 15:14 Adding to every value 17:40 Multiplying every value 19:52 Quick-fire questions 20:49 Exam-style question: coffee at the café 22:05 Recap #IBMaths #IBMathsAI #Statistics