Question

# **ECO250**

**Unit 4 In-Class Exercise**

- What is a random

variable? Give an example.

Suppose you are shopping online for a new toy for your dog. As you look at the product reviews, you see the following distribution of ratings. Use this table for questions 2-5.

- Sketch a data visualization of the distribution of stars.

- What is the probability that a randomly chosen reviewer gave the dog toy 3 stars? What is the probability that a randomly chosen reviewer gave the dog toy 3 or fewer stars?

- Find the expected value for the number of stars.

- Find the standard deviation of the number of stars.

- Write down the formula for the binomial distribution. What do
*n*,*x*, and represent in the formula? What does*n*! mean?

- As you shop for dog treats, a seller advertises that 95% of veterinarians recommend their treats. Suppose you randomly choose 10 veterinarians and ask whether they recommend this seller's treats.
- What is the probability that exactly nine veterinarians in your sample recommend the seller's treats?

- What is the probability that more than eight veterinarians in your sample recommend the seller's treats?

#### Top Answer

3). p=0.40 4). E(x)=3.5 5). standard... View the full answer