# Ex 13.2, 5 - Chapter 13 Class 11 Statistics

Last updated at April 16, 2024 by Teachoo

Chapter 13 Class 11 Statistics

Serial order wise

Last updated at April 16, 2024 by Teachoo

Ex 13.2, 5 - Chapter 15 Class 11 Statistics - NCERT Find the mean and variance for the data xi fi fixi xi-x ̅ (xi-x ̅ )^2 〖f_i (xi-x ̅ )〗^2 92 3 276 92 – 100 = –8 (-〖8)〗^2= 64 64 × = 92 93 2 186 93 – 100 = –7 (〖-7)〗^2= 49 49 × 2 = 98 97 3 291 97 – 100 = –3 (〖-3)〗^2= 9 9 × 3 = 27 98 2 196 98 – 100 = –2 (〖-2)〗^2= 4 4 × 2 = 8 102 6 612 102 – 100 = 2 (〖2)〗^2= 4 4 × 6 = 24 104 3 312 104 – 100 = 4 (〖4)〗^2= 16 16 × 3 = 48 109 3 327 109 – 100 = 9 (〖9)〗^2= 81 81 × 3 = 243 22 2200 Mean(𝑥 ̅) = (∑▒𝑓𝑖𝑥𝑖)/(∑▒𝑓𝑖) 𝑥 ̅ = 2200/22 𝒙 ̅ = 100 Now, finding variance ∑▒〖𝑓_𝑖 (𝑥𝑖−𝑥 ̅ )2〗=640 ∑▒𝑓𝑖=22 Variance (σ2) = (∑▒〖𝑓_𝑖 (𝑥𝑖 − 𝑥 ̅ )2〗)/(∑▒𝑓𝑖) = 640/22 = 29.09