Negative Correlation Analysis
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A negative correlation (r = -0.45) is found between average weekly hours spent playing with non-sibling children at age four and number of days sick in kindergarten. Answer the following questions based on this result.
1. What does a negative correlation mean in this specific scenario?
2. Calculate the coefficient of determination for this scenario.
3. If a journalist made an error in causality when writing an article about these findings, what would they be concluding based on this scenario (one sentence is sufficient)?
4. If this researcher had a sample size of 20 and started with a directional hypothesis, what was the critical r value (using the table in your textbook)?
5. Should she accept or reject her null hypothesis?
6. If the researcher concludes that there is no relationship between hours played with nonsiblings and number of sick days but in fact, there is, what type of decision did s/he make (Type I error / Type II error, or correct decision).
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Solution Summary
The solution consists of details of conducting a hypothesis test for the correlation between two variables.
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1. What does a negative correlation mean in this specific scenario?
It means that the more weekly hours spent playing with non-sibling children at age four, the less number of days sick in kindergarten.
2. Calculate the coefficient of determination for this scenario.
The coefficient of ...
Education
- BSc , Wuhan Univ. China
- MA, Shandong Univ.
Recent Feedback
- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
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