Technical Mathematics, Sixth Edition

Chapter 21. Introduction to Statistics and Probability

OBJECTIVES When you have completed this chapter, you should be able to Identify data as continuous, discrete, or categorical. Represent data as an x-y graph, scatter plot, bar graph, pie chart, stem and leaf plot, or boxplot. Organize data into frequency distributions, frequency histograms, frequency polygons, and cumulative frequency distributions. Calculate the mean, the weighted mean, the median, and the mode. Find the range, the quartiles, the deciles, the percentiles, the variance, and the standard deviation. Calculate the probabilities for frequency distributions, including the binomial and normal distributions. Estimate population means, standard deviations, and proportions within a given confidence interval. Make control charts for statistical process control. Fit a straight line to a set of data using the method of least squares.

Why study statistics? There are several reasons. First, for your work you might have to interpret statistical data or even need to collect such data and make inferences from it. For example, you could be asked to determine if replacing a certain machine on a production line actually reduced the number of defective parts made. Further, a knowledge of statistics can help you to evaluate the claims made in news reports, polls, and advertisements. A toothpaste manufacturer may claim that its product "significantly reduces" tooth decay. A pollster may claim that 52% of the electorate is going to vote ...