A sample of computer tablet batteries has a mean battery life of 28 months and standard deviation of 4 months What is the lifespan of batteries that are within the given standard deviations of the mean Use Notes Try it 1 1 1 standard deviation 2 2 standard deviations 24 32 20 36 Find the mean and standard deviation of the following sample of data Ex 2 4 6 49 67 58 55 62 70 52 65 60 58 28 12 15 17 22 25 19 23 15 26 5 4 0 2 7 3 0 3 3 3 3 3 7 3 7 4 0 3 0 2 3 The variance is o 15 7 The table shows sample data of how many minutes students spend on homework each night Ex 4 The mean of the data is x 225 The standard deviation is S 2 X 8 1 3 3 standard deviations 16 40 8 1 2 Last Season 10 3 20 27 35 17 20 13 17 This Season 23 17 28 16 23 16 16 10 13 90 75 60 85 65 80 70 75 8 The table shows the points scored by a community football team during two seasons Use the mean and standard deviation to determine during which season the team scored more consistently