Table of contents

1. Intro to Stats and Collecting Data1h 14m
2. Describing Data with Tables and Graphs1h 55m
3. Describing Data Numerically2h 5m
4. Probability2h 16m
5. Binomial Distribution & Discrete Random Variables3h 6m
6. Normal Distribution and Continuous Random Variables2h 11m
7. Sampling Distributions & Confidence Intervals: Mean3h 23m
8. Sampling Distributions & Confidence Intervals: Proportion1h 25m
9. Hypothesis Testing for One Sample3h 29m
10. Hypothesis Testing for Two Samples4h 50m
11. Correlation1h 6m
12. Regression1h 50m
13. Chi-Square Tests & Goodness of Fit1h 57m
14. ANOVA1h 57m

1. Intro to Stats and Collecting Data

Intro to Stats

Statistics

1. Intro to Stats and Collecting Data

Intro to Stats

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2:36 minutes

Problem 1.RE.2c

Textbook Question

Paying for First Dates USA Today posted this question on the electronic version of its newspaper: “Should guys pay for the first date?” Of the 1148 subjects who decided to respond, 85% of them said “yes.”

c. Does the survey constitute an experiment or an observational study?

Verified step by step guidance

Understand the definitions: An experiment involves manipulating one or more variables to determine their effect on a response variable, while an observational study involves observing subjects without manipulation.

Identify the key elements of the survey: The survey asked a question and recorded responses without manipulating any variables.

Determine if there was any manipulation: In this case, the survey simply collected opinions without altering any conditions or variables.

Recognize the nature of the data collection: Since the survey collected responses based on participants' existing opinions, it aligns with the characteristics of an observational study.

Conclude the type of study: Based on the lack of manipulation and the method of data collection, this survey is an observational study.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Experiment vs. Observational Study

An experiment involves manipulating one or more variables to observe the effect on another variable, often with random assignment to treatment groups. In contrast, an observational study involves observing subjects without manipulating any variables, simply recording data as it naturally occurs. Determining whether a study is experimental or observational is crucial for understanding the nature of the conclusions that can be drawn.

Sampling Bias

Sampling bias occurs when the sample collected is not representative of the population intended to be analyzed, often due to non-random selection methods. In the context of surveys, voluntary response bias is a common form of sampling bias, where individuals self-select to participate, potentially skewing results. Recognizing sampling bias is essential for evaluating the reliability and validity of survey findings.

Voluntary Response Sample

A voluntary response sample is a type of non-probability sampling where participants choose to be part of the sample. This method often leads to biased results because those who feel strongly about the topic are more likely to respond, which may not reflect the views of the general population. Understanding this concept helps in assessing the limitations of survey data and the generalizability of its conclusions.

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Related Practice

Textbook Question

Birth Weights Refer to the sample described in Exercise 6. Because Bellevue Hospital Center agreed to provide the 100 birth weights, does the sample of birth weights constitute a voluntary response sample?

Textbook Question

Physicians’ Health Study In the Physicians’ Health Study, some of the subjects were treated with aspirin while others were given a placebo. For the subjects in this experiment, what is blinding?

Textbook Question

Paying for First Dates USA Today posted this question on the electronic version of its newspaper: “Should guys pay for the first date?” Of the 1148 subjects who decided to respond, 85% of them said “yes.”

a. What is wrong with this survey?

Textbook Question

b. Is the value of 85% a statistic or a parameter?

Textbook Question

Divorces and Margarine One study showed that there is a very high correlation between the divorce rate in Maine and per capita consumption of margarine in the United States. Can we conclude that either one of those two variables is the cause of the other?

Textbook Question

Sampling For each of the following, identify the term that best describes the type of sample: systematic, convenience, stratified, cluster, or simple random sample.

a. As Lipitor pills are being manufactured, a quality control plan is to select every 500th pill and test it to confirm that it contains 80 mg of atorvastatin.

Textbook Question

Sampling For each of the following, identify the term that best describes the type of sample: systematic, convenience, stratified, cluster, or simple random sample.

b. To test for a gender difference in the way that men and women make online purchases, Gallup surveys 500 randomly selected men and 500 randomly selected women.

Textbook Question

Sampling For each of the following, identify the term that best describes the type of sample: systematic, convenience, stratified, cluster, or simple random sample.

d. A statistics student creates a survey and presents it to fellow statistics students.

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