# Tag: Statistics

#### Solved (Free): Let $Y_1, Y2, \cdots, Y_n$ be independent random variables such that each $Y_i$ has a gamma distribution with parameters

Let $Y_1, Y2, \cdots, Y_n$ be independent random variables such that each $Y_i$ has a gamma distribution with parameters $\alpha_i$ and $\beta$. That is, the distributions of the $Y$'s might…

#### Solved: The time between release from prison and the commission of another crime is uniformly distributed between 0 and 5 years for a high-risk group

The time between release from prison and the commission of another crime is uniformly distributed between 0 and 5 years for a high-risk group. Give the equation and graph the…

#### Solved: The article “Modeling Sediment and Water Column Interactions for Hydrophobic Pollutants”

The article "Modeling Sediment and Water Column Interactions for Hydrophobic Pollutants" (Water Research : 1169-1174) suggests the uniform distribution on the interval from 7.5 to 20 as a model for…

#### Solved: The hardness of a piece of ceramic is proportional to the firing time. Assume that a rating system has been devised to rate the hardness of a ceramic piece

The hardness of a piece of ceramic is proportional to the firing time. Assume that a rating system has been devised to rate the hardness of a ceramic piece and…

#### Solved: Suppose that a class in elementary statistics was allocated 15 minutes to complete a quiz. It can be assumed that the time X it takes to complete

Suppose that a class in elementary statistics was allocated 15 minutes to complete a quiz. It can be assumed that the time X it takes to complete the quiz is…

#### Solved (Free): The following data represents viscosity measurements from a batch chemical process. The data is assumed to be normally distributed

The following data represents viscosity measurements from a batch chemical process. The data is assumed to be normally distributed. The batches are checked for conformance to specification. Batches whose viscosity…

#### Solved: The useful life of an electrical component is exponentially distributed with a mean of 2,500 hours

The useful life of an electrical component is exponentially distributed with a mean of 2,500 hours. a. What is the probability the circuit will last more than 3,000 hours? b.…

#### Solved (Free): A course has two quizzes of equal weight, a midterm examination that has twice the weight of a quiz

A course has two quizzes of equal weight, a midterm examination that has twice the weight of a quiz, and a final examination that has twice the weight of the…

#### Solved (Free): A western city has 18 police officers eligible for promotion. Eleven of the 18 are Hispanic

A western city has 18 police officers eligible for promotion. Eleven of the 18 are Hispanic. Suppose only five of the police officers are chosen for promotion and that one…

#### Solved (Free): Random samples of households were selected from each of three regions in a large metropolitan area. The number of households selected from

Random samples of households were selected from each of three regions in a large metropolitan area. The number of households selected from each region and the corresponding mean household incomes…