Final answer:
The question deals with normal distributions and statistical concepts like budget constraints, utility-maximization, and hypothesis testing, relevant to college-level introductory statistics.
Step-by-step explanation:
The student's question is concerning the normal distribution of their monthly phone bill costs, with a mean of $76 and a standard deviation of $9. This is a statistics problem typically covered in a college-level introductory statistics course. The student needs to understand how to work with normal distributions, which are a key concept in probability and statistics.
The self-check questions involve several different scenarios requiring the understanding and application of statistical methods such as budget constraints, utility-maximization, hypothesis testing, and analysis of variance. To tackle these questions, students need to be familiar with concepts such as mean, standard deviation, utility theory, and hypothesis testing procedures, such as t-tests and chi-squared tests.