Chapter 8: Problem 61
Under what assumptions are the estimates in the empirical rule exact?
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 8: Problem 61
Under what assumptions are the estimates in the empirical rule exact?
All the tools & learning materials you need for study success - in one app.
Get started for free
In a certain set of scores, the median occurs more often than any other score. It follows that (A) The median and mean are equal. (B) The mean and mode are equal. (C) The mode and median are equal. (D) The mean, mode, and median are all equal.
Pastimes A survey of all the students in your school yields the following probability distribution, where \(X\) is the number of movies that a selected student has seen in the past week: \begin{tabular}{|r|c|c|c|c|c|} \hline Number of Movies & 0 & 1 & 2 & 3 & 4 \\ \hline Probability & \(.5\) & \(.1\) & \(.2\) & \(.1\) & \(.1\) \\ \hline \end{tabular} Compute the expected value \(\mu\) and the standard deviation \(\sigma\) of \(X\). (Round answers to two decimal places.) For what percentage of students is \(X\) within two standard deviations of \(\mu\) ?
A survey of 52 U.S. supermarkets yielded the following relative frequency table, where \(X\) is the number of checkout lanes at a randomly chosen supermarket. \({ }^{23}\) $$ \begin{array}{|c|c|c|c|c|c|c|c|c|c|c|} \hline x & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\ \hline \boldsymbol{P}(\boldsymbol{X}=\boldsymbol{x}) & .01 & .04 & .04 & .08 & .10 & .15 & .25 & .20 & .08 & .05 \\ \hline \end{array} $$ a. Compute \(\mu=E(X)\) and interpret the result. HINT [See Example 3.] b. Which is larger, \(P(X<\mu)\) or \(P(X>\mu)\) ? Interpret the result.
\- Find an algebraic formula for the sample standard deviation of a sample \(\\{x, y\\}\) of two scores \((x \leq y)\).
Your friend Charlesworth claims that the median of a collection of data is always close to the mean. Is he correct? If so, say why; if not, give an example to prove him wrong.
What do you think about this solution?
We value your feedback to improve our textbook solutions.