# Quiz 3

Date: 02/07/2020

## Instructions:

Write your name in the top-right corner of the page. You are not allowed any resources other than a standard scientific, non-graphing calculator.

## Problems:

### Problem 1:

In each of the following sub-problems state what method of sampling is being used. Explain what is special about this sampling method in how the probability of a random individual being selected changes.

#### 1.1 Twitter poll (2 points):

In a Pew Research Center poll, 1007 adults were called after their telephone numbers were randomly generated by a computer, and 85% of the respondents were able to correctly identify what Twitter is.

#### 1.2 Public sentiment poll (2 points):

The City of Reno designs a sample of Reno adult residents in which all participants are broken into age groups: 18 - 25, 26 - 35, 36 - 45, 46 - 55, 56 and older. Individuals are selected randomly from these age groups, with total number of participants from each group selected proportionally to the percent of adult residents of this age in Reno.

### Problem 2:

For each sub-problem, refer to the frequency distribution on the left.

#### 2.1 (1 point)

Identify the upper class limits.

#### 2.2 (1 point)

What is the class width of the frequency distribution?

#### 2.3 (4 points)

Name three typical characteristics of normal data. Does the data in the frequency distribution seem “normal enough”? You must justify your answer based on each of the above criteria.