A nutritionist wants to determine if a new diet plan helps people lose weight more effectively than a standard diet. She randomly assigns 150150 participants to either the new diet plan or the standard diet and tracks their weight loss over 33 months. Is this study an observational study or an experiment? Explain your answer.

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1. Introduction to Statistics(0)

Intro to Stats
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Intro to Collecting Data
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Sampling Methods
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2. Describing Data with Tables and Graphs(0)

Visualizing Qualitative vs. Quantitative Data
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Frequency Distributions
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Histograms
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Bar Graphs and Pareto Charts
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Pie Charts
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Frequency Polygons
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Time-Series Graph
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3. Describing Data Numerically(0)

Mean
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Median
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Mode
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Standard Deviation
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Interpreting Standard Deviation
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Percentiles & Quartiles
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Addition Rule
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Multiplication Rule: Independent Events
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Introduction to Contingency Tables
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Bayes' Theorem
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Fundamental Counting Principle
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Uniform Distribution
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Non-Standard Normal Distribution
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7. Sampling Distributions & Confidence Intervals: Mean(0)

Sampling Distribution of the Sample Mean and Central Limit Theorem
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Introduction to Confidence Intervals
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Determining the Minimum Sample Size Required
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Sampling Distribution of Sample Proportion
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Chi Square Distribution
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Two Proportions
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Two Means - Unknown, Unequal Variance
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Two Means - Unknown, Equal Variance
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Two-Way ANOVA
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Problem 20Multiple Choice

A nutritionist wants to determine if a new diet plan helps people lose weight more effectively than a standard diet. She randomly assigns $150$ participants to either the new diet plan or the standard diet and tracks their weight loss over $3$ months. Is this study an observational study or an experiment? Explain your answer.

An observational study, because the nutritionist is observing the participants over time

An observational study, because the participants are following a diet plan

An experiment, because the nutritionist is manipulating the type of diet the participants follow, randomly assigning them to groups, and tracking the outcome over time

An experiment, because the nutritionist assigns a sufficiently large number of participants

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