1. Were the groups in this study independent or dependent? Provide a rationale for your answer.

The groups in this study are independent or unrelated groups that are formed by the random assignment of subjects to the treatment and comparison groups. Groups are selected from two different settings, two different points in time and are not matched in any way.

2. t –3.1 describes the difference between women and men for what variable in this study? Is this value significant? Provide a rationale for your answer. t= -3.15 describes the difference between women and men for Mental Health variable in this study. This value is significant since the t-test yields a p value, which is .002 less than alpha .05, it can cause the null hypothesis to be rejected.

3. Is t –1.99 significant? Provide a rationale for your answer. Discuss the meaning of this result in this study.

t –1.99 describes the difference in health functioning between women and men after a MI. It is significant on this study as the P value is 0.049 which is close and still less to the alpha 0.05 which is enough evidence to reject to the null hypothesis.

4. Examine the t ratios in Table VI. Which t ratio indicates the largest difference between the males and females post MI in this study? Is this t ratio significant? Provide a rationale for your answer.

The mental health t-ratio indicates the largest difference between the males and females post MI in this study. The t -score is -3.15. This t- ratio is significant since it is causing the p value to be significantly low, less than the alpha 0.05.

5. Consider t –2.50 and t –2.54. Which t ratio has the smaller p value? Provide a rationale for your answer. What does this result mean?

The t ratio with -2.54 has the smaller p value since larger the...

...1. Were the groups in this study independent or dependent? Provide a rationale for your answer.
Independently due to the data being collected independently
2. t = −3.15 describes the difference between women and men for what variable in this study? Is this value significant? Provide a rationale for your answer.
t = -3.15 describes mental health in this study. This is significant because mental health plays a big role in the outcome of MI patients.
3. Is t = −1.99 significant? Provide a rationale for your answer. Discuss the meaning of this result in this study.
t = -1.99 describes health functioning. This is very significant. It is used to describe decline from illness or disease. It could solely explain change in quality of life post MI.
4. Examine the t ratios in Table VI. Which t ratio indicates the largest difference between the males and females post MI in this study? Is this t ratio significant? Provide a rationale for your answer.
Mental health revealed the largest difference between the males and females post MI in this study. This is significant because it truly reveals that men and women cope differently. I also believe this value would be inaccurate due to men being less likely to admit that they have mental health issues.
5. Consider t = −2.50 and t = −2.54. Which t ratio has the smaller p value? Provide a rationale for your answer. What does this result mean?
-2.54 has the smaller p value at 0.007. It shows the health outcome between...

...PEARSON’S PRODUCT-MOMENT CORRELATION COEFFICIENT
ANSWERS TO EXERCISE 23
Question 1
The r value for the relationship between Hamstring strength index 60o and the Shuttle run test is -0.149. This r value shows a weak correlation between the two variables, as it is less than the 0.3 threshold for significance. Therefore, the r value is not significant.
Question 2
Between r=1.00 and r=-1.00, there is no difference in terms of strength. Both values are on the extreme ends of the spectrum and signify the maximum significance within the r value scale. A value of 1.00, whether negative or positive, shows that the two variables have a perfect linear relationship, and as such, the independent variable can be used to accurately predict the value of the dependent variable. The only difference is that the negative value signifies that a rise in one variable causes the corresponding variable to drop while the positive value signifies that the rise in one variable causes the corresponding variable to increase in value as well. But strength wise, they are similar.
Question 3
The relationship between the hamstring strength index 60o and shuttle run test index is a negative one. This is signified by the negative nature of the r value (-0.498). A negative relationship occurs when a rise in one variable causes the corresponding variable to decrease in value.
Question 4
This research study had the primary objective of measuring the relationship between muscle strength and...

...9Name: Brielle Cantagallo Class: Statistics
Date: 3/17/13
□ EXERCISE29 Questions to be Graded
* 1.Were the groups in this study independent or dependent? Provide a rationale for your answer.
The groups in this study were independent because the two sets of data were not taken from the same subjects. The subjects were in one group: female and the second group: male.
* 2.t = −3.15 describes the difference between women and men for what variable in this study? Is this value significant? Provide a rationale for your answer.
t= -3.15 describes the difference between men and women for the variable of mental health. This value is significant because 0.002 is less than the alpha type 1 error rate of 0.05 that was used.
* 3.Is t = −1.99 significant? Provide a rationale for your answer. Discuss the meaning of this result in this study.
t= -1.99 is significant because it shows that the physical functioning and health functioning of both the men and women in this study were almost the same across the board. The p value of 0.049 was also the same in each of these variables concluding that the type 1 error rate for this was less than the alpha 0.05 that was set for this study.
* 4.Examine the t ratios in Table VI. Which t ratio indicates the largest difference between the males and females post MI in this study? Is this t ratio significant? Provide a rationale for your answer.
The t ratio that was the largest difference...

...of 1000 flights and proportions of three routes in the sample. He divides them into different sub-groups such as satisfaction, refreshments and departure time and then selects proportionally to highlight specific subgroup within the population. The reasons why Mr Kwok used this sampling method are that the cost per observation in the survey may be reduced and it also enables to increase the accuracy at a given cost.
TABLE 1: Data Summaries of Three Routes
Route 1
Route 2
Route 3
Normal(88.532,5.07943)
Normal(97.1033,5.04488)
Normal(107.15,5.15367)
Summary Statistics
Mean
88.532
Std Dev
5.0794269
Std Err Mean
0.2271589
Upper 95% Mean
88.978306
Lower 95% Mean
88.085694
N
500
Sum
44266
Summary Statistics
Mean
97.103333
Std Dev
5.0448811
Std Err Mean
0.2912663
Upper 95% Mean
97.676525
Lower 95% Mean
96.530142
N
300
Sum
29131
Summary Statistics
Mean
107.15
Std Dev
5.1536687
Std Err Mean
0.3644194
Upper 95% Mean
107.86862
Lower 95% Mean
106.43138
N
200
Sum
21430
From the table above, the total number of passengers for route 1 is 44,266, route 2 is 29,131 and route 3 is 21,430 and the total numbers of passengers for 3 routes are 94,827.
Although route 1 has the highest number of passengers and flights but it has the lowest means of passengers among the 3 routes. From...

...Exercise29 - Statistics work book
SUMITHA THOMAS
GRAND CANYON UNIVERSITY
Exercise29 - Statistics work book
Name:____Sumitha K Thomas________________________________________ Class: ____________________
Date: ___3/10/2013______________________________________________________________________________
□ EXERCISE29 Questions to be Graded
1. Were the groups in this study independent or dependent? Provide a rationale for your answer.
Groups are independent in this study. According to the above data independent groups define as if the two sets of data were not taken from the same subjects and if the scores are not related. In this study subjects are two different genders which is men and women and scores are not even related each other. Therefore this is an independent study.
2. t = −3.15 describes the difference between women and men for what variable in this study? Is this value significant? Provide a rationale for your answer.
T = -3.15 describes the mental health variability. This is a significant value because it’s provides the degree of freedom. According to the data above the significance of a t ratio can be determined by comparison with the critical values in a statistical table for the t distribution using the degree of freedom for the study. The value is significant because p value of it is 0.002 which is smaller than alpha value set for...

...EXERCISE 36
6. Can ANOVA be used to test proposed relationships or predicted correlations between variables in a single group? Provide rationale for your answer.
ANOVA cannot be used to test proposed relationships or predicted correlations between variables in a single group because it is designed to test for correlations and interactions amongst groups, i.e. in the test group of patients with OA you are testing the correlations between those who do not use GI and PMR and those that do. Although all participants suffered from OA they were separated into two groups for comparison.
7. If a study had a result of F(2, 147) = 4.56, p=0.003, how many groups were in the study, and what was the sample size?
Number of groups = K
Group degrees of freedom= K-1+=2 = K=2+1=3
K=3 which means the number of groups = 3
Sample size = N
Error degrees of freedom = N-K = 147=N-3 = N=147+3 = 150
N=150 which means the sample size is 150
8. The researchers state that the sample of their study was 28 women with a diagnosis of OA, and that 18 were randomly assigned to the intervention group and 10 were randomly assigned to the control group. Discuss the studies strengths and/or weaknesses in this statement.
One of the biggest weaknesses in this study is the number of participants. There are only 18 women participating. With a larger group of participants you can obtain more credible and concrete results. One of the strengths is that there is in fact a control group, so...

...Annamma Thomas
Exercise29
1. The groups were independent because the men and women participating in the experiment did not share any relationships and their quality of life tests were totally independent of one another.
2. The variable described by this number is mental health. Since the P value is .002 and the alpha is .05, the difference can cause the null hypothesis to be rejected.
3. The T-Value is significant because the P value is .049 which is the closest to the alpa which is .05. Since this is one of the values that allows the selected hypothesis to be correct the significance is support to the performed experiment.
4. The mental health variable seems to have the biggest difference between men and woman. The t-score shows a -3.15 difference and although this seems huge the P-score diminishes the amount of certainty thee data provides since it is significantly lower than the alpha.
5. The t=-2.54 has a smaller P-Score. This shows that the physical component score has a lot more to do with the quality of life function within men and woman.
6. A type I error is when a true null hypothesis is rejected. Certain variables that have a P-score that is lower than the alpha would need multiple trials to ensure that the null hypothesis should be rejected since outliers are a commonality and multiple trials ensure that data is correct.
7. A Bonferroni procedure would be helpful since it would counteract the problem of multiple...

...EXERCISE29 t-TEST FOR INDEPENDENT GROUPS I
STATISTICAL TECHNIQUE IN REVIEW
The t-test is a parametric analysis technique used to determine significant differences between the scores obtained from two groups. The t-test uses the standard deviation to estimate the standard error of the sampling distribution and examines the differences between the means of the two groups. Since the t-test is considered fairly easy to calculate, researchers often use it in determining differences between two groups. When interpreting the results of t-tests, the larger the calculated t ratio, in absolute value, the greater the difference between the two groups. The significance of a t ratio can be determined by comparison with the critical values in a statistical table for the t distribution using the degrees of freedom (df) for the study. The formula for df for an independent t-test is:
df = number of sobjects in sample 1 + number of subjects in sample 2 - 2
The t-test can only be used once to examine data from two study samples, otherwise the Type 1 error rate (alpha) may be inflated. A Type I error occurs when the researcher rejects the null hypothesis when it is in actuality true. Thus if researchers run multiple t-tests to evaluate differences of various aspects of a study's data, this is considered a misuse of the t-test and often leads to an increased risk for a Type I error or finding two groups significantly different when they are...