-Anyone wanna help a sister out??-
2 answers:
Answer:
Option A - The researcher made an error because −1 ≤ r ≤ 1.
Step-by-step explanation:
Given : A researcher is trying to find out if there is a correlation between the U.S. economy and the number of hours spent on social media. The researcher determines that the correlation coefficient is r = 1.26.
To find : What does this value mean?
Solution :
By definition of correlation coefficient,
The correlation coefficient r measures the strength and direction of a linear relationship between two variables on a scatter plot.
The value of r is always between +1 and –1 i.e,
According to researcher,
The correlation coefficient is r = 1.26 >1
So, From the options it means
The researcher made an error because −1 ≤ r ≤ 1.
Therefore, Option A is correct.
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Answer:
The hippocampus volumes in the alcoholic adolescents are less than the normal volume of 9.02 cm³
Step-by-step explanation:
Let x= the hippocampus volumes in the alcoholic adolescents
We'll conduct a hypothesis test at the 0.01 significance level with
Null hypothesis: x = 9.02 cm³
Alternate hypothesis: x < 9.02 cm³
A sample of 13 alcoholic adolescents gives the parameters
size=N= 13
mean=M= 8.12 cm³
standard deviation= s= 0.8 cm³
According to the sample, with 99% confidence, t statistic for the value X=9.02 can be found using the formula:
t= where
- M is the sample mean (8.12)
- s is the standard deviation of the sample (0.8)
- N is the sample size (13)
If we put these numbers in the formula:
t= =4.056
One tailed critical value for the sample with 12 degrees of freedom (sample size-1) in 99% confidence level is 2.681.
Since t value (4.056) is bigger than the critical value, we fail to reject the alternate hypothesis, therefore reject the null hypothesis and accept alternate hypothesis.