The EPIC-Norfolk study, a study of diet and cancer in Great Britain, was performed to assess the relationship between dietary intake of vitamin C, plasma levels of vitamin C (in blood), and other predictors. One hypothesis is that smokers might have different vitamin C intake and vitamin C plasma levels than nonsmokers. Dietary intake of vitamin C was obtained using 7-day diet records in which a subject recorded what he or she ate in real time and a computer program was used to estimate nutrient intake based on the diet record data. The data obtained for current smokers and nonsmokers are presented as follows: Assuming unequal variances, is there a significant difference of the mean of the Vitamin C intake between the two groups? 1.What are the appropriate hypotheses? 2. What is the computed test statistic? 3. What is the p-value? 4. What is the appropriate decision based on the p-value? 5. What is the implication of the decision made above?
Correlation
Correlation defines a relationship between two independent variables. It tells the degree to which variables move in relation to each other. When two sets of data are related to each other, there is a correlation between them.
Linear Correlation
A correlation is used to determine the relationships between numerical and categorical variables. In other words, it is an indicator of how things are connected to one another. The correlation analysis is the study of how variables are related.
Regression Analysis
Regression analysis is a statistical method in which it estimates the relationship between a dependent variable and one or more independent variable. In simple terms dependent variable is called as outcome variable and independent variable is called as predictors. Regression analysis is one of the methods to find the trends in data. The independent variable used in Regression analysis is named Predictor variable. It offers data of an associated dependent variable regarding a particular outcome.
The EPIC-Norfolk study, a study of diet and cancer in Great Britain, was performed to assess the relationship between dietary intake of vitamin C, plasma levels of vitamin C (in blood), and other predictors. One hypothesis is that smokers might have different vitamin C intake and vitamin C plasma levels than nonsmokers. Dietary intake of vitamin C was obtained using 7-day diet records in which a subject recorded what he or she ate in real time and a computer program was used to estimate nutrient intake based on the diet record data. The data obtained for current smokers and nonsmokers are presented as follows:
Assuming unequal variances, is there a significant difference of the mean of the Vitamin C intake between the two groups?
1.What are the appropriate hypotheses?
![Association between current smoking
and diet record intake of vitamin C in
the EPIC-Norfolk Study
Mean vitamin C
Group
intake (mg/day)
sd (mg/day)
N
Nonsmokers
92.5
50.4
306
Smokers
57.0
26.3
17
•Diet record intake includes intake from foods but not from
vitamin supplements.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdefcb7d2-e177-4f90-914d-ef179418201c%2F54b0a25b-dd1f-4810-89b7-57dfe169a45c%2Feph60q_processed.png&w=3840&q=75)
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The independent variable is the association between current smoking and diet record intake of vitamin C.
There are two groups which are named as Nonsmokers and Smokers.
We have to test whether there is a difference of the mean of the Vitamin C intake between the two groups or not.
This test two-independent sample t test with unequal variances and this is two tailed test.
Null hypothesis:
There is no difference of the mean of the Vitamin C intake between the two groups.
Alternative hypothesis:
There is a difference of the mean of the Vitamin C intake between the two groups.
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