A psychologist wants to compare the variability in reaction times between two groups: those who slept 88 hours, with a sample size of 2020 and a standard deviation of 0.950.95 seconds, and those who slept 44 hours, with a sample size of 2020 and a standard deviation of 0.380.38 seconds. At the 0.050.05 significance level, test the claim that both groups have the same amount of variation in reaction times.

There is sufficient evidence to support the claim that the group with 88 hours of sleep has a larger variation in reaction times than the group with 44 hours of sleep.

There is insufficient evidence to support the claim that the group with 88 hours of sleep has a larger variation in reaction times than the group with 44 hours of sleep.

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1. Intro to Stats and Collecting Data(0)

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Levels of Measurement
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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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Dot Plots
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Stemplots (Stem-and-Leaf Plots)
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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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Boxplots
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4. Probability(0)

Basic Concepts of Probability
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Complements
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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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Multiplication Rule: Dependent Events
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Bayes' Theorem
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Fundamental Counting Principle
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Counting
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5. Binomial Distribution & Discrete Random Variables(0)

Discrete Random Variables
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Binomial Distribution
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Poisson Distribution
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Hypergeometric Distribution
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6. Normal Distribution and Continuous Random Variables(0)

Uniform Distribution
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Standard Normal 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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Confidence Intervals for Population Mean
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Determining the Minimum Sample Size Required
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8. Sampling Distributions & Confidence Intervals: Proportion(0)

Sampling Distribution of Sample Proportion
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Confidence Intervals for Population Proportion
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Chi Square Distribution
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Confidence Intervals for Population Variance
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9. Hypothesis Testing for One Sample(0)

Steps in Hypothesis Testing
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Performing Hypothesis Tests: Means
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Performing Hypothesis Tests: Proportions
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Performing Hypothesis Tests: Variance
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Critical Values and Rejection Regions
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Link Between Confidence Intervals and Hypothesis Testing
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Type I & Type II Errors
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10. Hypothesis Testing for Two Samples(0)

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 Means - Known Variance
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Two Means - Matched Pairs (Dependent Samples)
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Two Variances and F Distribution
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11. Correlation(0)

Scatterplots & Intro to Correlation
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Correlation Coefficient
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12. Regression(0)

Linear Regression & Least Squares Method
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Quadratic Regression
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13. Chi-Square Tests & Goodness of Fit(0)

Goodness of Fit Test
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Contingency Tables
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Independence Tests
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Homogeneity Tests
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14. ANOVA(0)

Introduction to ANOVA
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Multiple Comparisons: Tukey Test
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Multiple Comparisons: Tukey-Kramer Test
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Multiple Comparisons: Bonferoni Test
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Two-Way ANOVA
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10. Hypothesis Testing for Two Samples

Two Variances and F Distribution

10. Hypothesis Testing for Two Samples

Two Variances and F Distribution: Videos & Practice Problems

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Problem 7Multiple Choice

A psychologist wants to compare the variability in reaction times between two groups: those who slept $8$ hours, with a sample size of $20$ and a standard deviation of $0.95$ seconds, and those who slept $4$ hours, with a sample size of $20$ and a standard deviation of $0.38$ seconds. At the $0.05$ significance level, test the claim that both groups have the same amount of variation in reaction times.

There is sufficient evidence to warrant rejection of the claim that both groups have the same amount of variation in reaction times.

There is insufficient evidence to warrant rejection of the claim that both groups have the same amount of variation in reaction times.

There is sufficient evidence to support the claim that the group with $8$ hours of sleep has a larger variation in reaction times than the group with $4$ hours of sleep.

There is insufficient evidence to support the claim that the group with $8$ hours of sleep has a larger variation in reaction times than the group with $4$ hours of sleep.

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