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Posted by **jhikjhak** on Tuesday, January 15, 2013 at 1:49am.

Now, we examine the relationship between cry time and group among infants at Northbay.

1. Suppose we wish to perform a two-sample test, but we do not want to make any normality (or other strong parametric) assumptions. Conduct an appropriate non-parametric test to test whether the distribution of cry time is the same in both groups at the 0.05 level of significance.

What is your p-value?

unanswered

Your conclusion from the test?

there is evidence that the *means* of the two groups are different (specifically, there is evidence that the mean is higher in the control group) there is not evidence that the *means* of the two groups are different none of the above

You have used 0 of 2 submissions

• 2. Assuming randomization was successful and all participants complied with their assigned exposure, which of the following should we be concerned about:

Confounding by sex of the infant Confounding by the amount of pain experienced by the infant Effect modification by sex of the infant Misclassification of the exposure status of the infant

You have used 0 of 1 submissions

• Exploratory Analysis

Before jumping into analyzing the babies.dta dataset, first explore the dataset using summary statistics and graphical analyses.

1. Make a boxplot of cry time by group. According to the boxplot, which group has more variability in cry time?

control intervention

You have used 1 of 1 submissions

• 2. Using the central limit theorem, construct a 95% confidence interval for the average total cry time for infants in the control group and infants in the intervention group. For this question only, assume that the standard deviation of cry time within each group is known and is equal to 22 seconds.

Control

Lower Bound

unanswered

Upper Bound

unanswered

Intervention

Lower Bound

unanswered

Upper Bound

- statistics -
**jhikjhak**, Tuesday, January 15, 2013 at 5:46amplease answer, any body, any expert

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**mark**, Tuesday, January 15, 2013 at 2:48pmdid you get an answer?

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**seriously?**, Tuesday, January 15, 2013 at 11:50pmWhy not answer it yourself? This is from a free edX subject exam. If after 12 weeks you can't answer a few very easy questions, then what have you been doing? Obviously not the work.

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**jhikjhak**, Friday, January 18, 2013 at 6:49amHi netspirit, can you answer these

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**jhikjhak**, Friday, January 18, 2013 at 6:52amCan you please answer problem no.2 of exploratory analysis( Using central limit theorem)

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**jhikjhak**, Saturday, January 19, 2013 at 7:04amplease help with the central limit theorem problem

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**shanaya**, Sunday, January 20, 2013 at 4:22pmwhat does the 22 seconds do in this question??? i found the upper and lower bound for the intervention but the control answers were incorrect. explain plz.

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**heheeee**, Monday, January 21, 2013 at 2:18amupper and lower bound answer plzzzz