# Lesson 6 Let’s Investigate Solidify Understanding

Solve each system of equations.

### 1.

### 2.

### 3.

### 4.

### 5.

### 6.

### 7.

### 8.

For the following scenarios, identify each situation as a survey, observational study, or an experiment.

### 9.

To determine if a new pain medication is effective, researchers randomly assign two groups of people to use the pain medication in group 1 and a placebo in group 2. Both groups are asked to rate their pain and the results are compared.

#### A.

survey

#### B.

observational study

#### C.

experiment

### 10.

Officials want to determine if raising the speed limit from

#### A.

survey

#### B.

observational study

#### C.

experiment

### 11.

To determine if a new sandwich on the menu is preferred more than the original, the manager of the restaurant takes a random sample of customers who have tried both sandwiches and asks them which sandwich they like best.

#### A.

survey

#### B.

observational study

#### C.

experiment

### 12.

A newspaper wants to know how satisfied their customers are. It randomly selects

#### A.

survey

#### B.

observational study

#### C.

experiment

Mrs. Williams wants to know if doing practice problems actually helps students do better on their unit exams.

### 13.

Describe how Mrs. Williams could carry out a survey to determine if practice helps. Explain the role of randomization in your design.

### 14.

Describe how Mrs. Williams could carry out an observational study to determine if practice problems help test scores.

### 15.

Describe how Mrs. Williams could carry out an experiment to determine if practice problems help test scores. Explain how you will use randomization in your design and how you will use a control.

### 16.

If Mrs. Williams wants to determine if practice problems cause test scores to rise, which method would be best? Why?

### 17.

The average resting heart rate of a young adult is approximately

Draw and label the normal curve that describes this distribution. Be sure to label the mean, and the measurements

, , and standard deviations out from the mean. What percent of people have a heart rate between

and per minute? Label these points on your normal curve above and shade in the area that represents the percent of people with heartbeats between and per minute.

### 18.

If a resting heart rate above