STA215H5 Lecture Notes - Lecture 2: Categorical Variable, Standard Deviation, Central Tendency

• School: UTM
• Department: Statistics
• Course: STA215H5
• Professor: Samantha Jo-Caetano

Document Summary

Lec101 notes: unit 2 numeric data summaries. Unit 2 objectives: be able to calculate summary numbers (mean, median, mode, standard deviation, variance, range, catego(cid:396)ize (cid:374)u(cid:373)(cid:271)e(cid:396)s as (cid:862)sp(cid:396)ead(cid:863) o(cid:396) (cid:862)(cid:373)iddle(cid:863) of data, determine when mean, median, mode are most appropriately used. Numeric summaries: center (location), variability (spread) Numeric data: x: used to represent an observation. N: used to represent the total number of observations: all observations together are called a sample. Numeric data location: the mean (sample mean) average of all observations. Example: {45. 1, 53. 0, 50. 6, 51. 1, 50. 1} calculate the mean length: notation: (cid:454) , calculation: (cid:454) = (cid:454) = = (cid:2872)(cid:2873). (cid:2869)+(cid:2873)(cid:2871). (cid:2868)+ (cid:2873)(cid:2868). (cid:2874)+ (cid:2873)(cid:2869). (cid:2869)+ (cid:2873)(cid:2868). (cid:2869) (cid:2873, the median is the (cid:862)(cid:373)iddle(cid:863) of the o(cid:271)se(cid:396)(cid:448)atio(cid:374) =4(cid:891). (cid:891)(cid:890: to find median, list numbers/observations from least to greatest. If (cid:862)(cid:374)(cid:863) = odd, the (cid:373)iddle (cid:374)u(cid:373)(cid:271)e(cid:396) is the (cid:373)edia(cid:374) If (cid:862)(cid:374)(cid:863) = e(cid:448)e(cid:374), the a(cid:448)e(cid:396)age of the t(cid:449)o (cid:374)u(cid:373)(cid:271)e(cid:396)s is the (cid:373)edia(cid:374)