ISI
Lab 4

1: Introduction 2: Files Needed 3: Explore data 4: Numerical 5: Graphical 6: Discussion 7: Thought Questions 8: Statistical Inference 9: Two Proportions Applet 10: Analysis 11: Confession 12: Confidence Interval 13: Conclusions 14: Summary

Confidence Interval

Even though the difference is not statistically significant, let's practice interpreting a confidence interval.

(t) First, use the 2SD method to approximate a 95% confidence interval:

• What value did the applet give you for the standard deviation of the null distribution?
• Extend that distance on each side of the observed statistic.

lower bound = observed difference - 2 SD
upper bound = observed difference + 2SD

(u) Use the applet to determine the theory-based confidence interval.

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•  At the bottom of the first column in the applet, check the box to display 95% CI(s) for difference in proportions
• Take a screen shot of your results and add to your report.

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Are the intervals similar?

Rememberm to interpret the interval as the difference in probabilities, indicating the direction and the size of the difference. This is a bit tougher when zero is in the interval!

We are 95% confident that
Choose one The probability of yawning after a yawn seed The probability of yawning without a yawn seed is up to ## Choose onelargersmaller than Choose oneThe probability of yawning after a yawn seed The probability of yawning without a yawn seed
OR
Choose one The probability of yawning after a yawn seed The probability of yawning without a yawn seed is up to ## Choose onelargersmaller than Choose oneThe probability of yawning after a yawn seedThe probability of yawning without a yawn seed