Spell-checking software. Spell-checking software catches nonword errors, which are strings of letters that are not words, as when the is typed as eth. When undergraduates are asked to write a 250-word essay (without spell-checking), the number X of nonword errors has the following distribution: Value of X 0 1 2 3 4 Probability 0.1 0.3 0.3 0.2 0.1 (a) Sketch the probability distribution for this random variable. (b) Write the event at least one nonword error in terms of X. What is the probability of this event? (c) Describe the event X 2 in words. What is its probability? What is the probability that X 2?

Chapter 2 Exploring Data with Graphs and Numerical Summaries 2.1 Different Types of Data Categorical Variables: These are variables that you can put into different groups, generally non-numerical answers. Things like favorite colors, political party afﬁliation, or letter grades are categorical variables. Quantitative Variables: These are variables that are represented by numerical values. An amount of something. There are two types are quantitative variables: Discrete: these are characterized as having a FINITE amount of possible outcomes. Continuous: these, on the other hand, have an inﬁnite list of possible outcomes and can generally be measured. Note: For quantitative data: there are two key features. Example: The class list below has all the information for ea