# Stats - Unit 1

 Statistics (the study of) Science of collecting, organizing, summarizing, and analyzing data to draw conclusions and answer questions Population the entire group of people being studied Sample Subset of population that is being studied Individual A person or object that is a member of the poopulation being studied Statistic a numerical summary of a sample s=sample Parameter numerical summary of a population p=pop Descriptive Statistics Describe data through numerical summaries - tables and graphs Inferential Statistics Take a result form a sample - extend to the pop - measure reliability of result Variable Characteristics of the individual within a populationEX weight, height, age Qualitative vs. Quantitative Qualitative- classification based on a characteristic (gender, eye color)Quantitative- numerical measurements of individuals (age, weight, shoe size) Difference is when added together, one means something, and the other does not or cannot be added together Discrete vs. Continuous Discrete- an infinite # of values that are countable (# of facebook friends - cannot have half a fb friend)Continuous- an infinite # of values that are not countable (weight, age - can weigh 110.5 lbs) What are the 5 types of sampling? 1- simple random sampling2- systematic3- stratified4- cluster5- convenience Simple Random Sampling (SRS) equal chance for each person or group of people to be picked for the sample Systematic select every kth individual from the population EX randomly select a starting point and survey every 5th person Stratified divide population into non-overlapping homogenous groups - randomly select sample from every strata EX divide class into 2 strata (shoes & boots) then randomly select 10 students from each group = sample Cluster divide population into non-overlapping groups call clusters - randomly select clusters (not all are chosen) and sample every indivudual Convenience sampling whomever is convenient Histogram Constructed by drawing rectangles for each class of data - height of rectangle is the frequency of the class. Same width and always touching Lower vs. Upper limit Lower- the smallest value within a classUpper- the largest value within a class Class Width the difference between consecutive lower class limits class width = largest data value - smallest data value / number of classes Stem and Leaf Plot -represent quantitative data graphically-numbers on the left (stem) represent the first few digits-number on the right (leaf) represent the last few digits-leaves are stacked on the right side What are the measures of central tendency? MeanMedianMode Population arithmetic mean μ computed by using all of the individuals in a populationpop mean = paramater Sample arithmetic mean x bar computed using sample datasamp mean = statistic AuthorAnonymous ID67982 Card SetStats - Unit 1 DescriptionStatistics unit one definitions Updated2011-02-22T00:53:56Z Show Answers