220x Filetype PPTX File size 0.19 MB Source: www.ysgolcalon.cymru
Key Vocabulary Median Mean Mode Modal class Range Statistics • When we gather data, we end up with a mass of numbers. • These numbers, by themselves, are meaningless • They gain meaning when we perform calculations on the numbers, creating statistics. Types of statistic • There are 2 types of statistic which are more important than any others • Whenever we are asked to describe a population or to compare two populations, we always use both of these types of statistic Averages -mean, mode and median Measures of spread -range We are going to be looking at finding these statistics from grouped frequency tables Types of average • Mode The value that occurs most often in the data. • Median Put the data in order. The median is the middle value. If there are two middle values, take the mean average of the two. • Mean Add all the numbers together and divide by how many numbers there are. Example The following shows the weekly wage of a sample of some professional footballers We are going to calculate an estimate of the mean, an estimate of the median, and find the modal class.