Please help me they are mulitple choice Question 1 The samples used in two-sampl
ID: 3254962 • Letter: P
Question
Please help me they are mulitple choice
Question 1
The samples used in two-sample t procedures can be of different sizes.
True
False
1 points
QUESTION 2
You have two independent samples of size 24 and 27. You conduct a hypothesis test and obtain a p-value. Using the conservative method what would you use for the degrees of freedom for comparison?
24
27
23
26
49
1 points
QUESTION 3
A study was conducted to estimate the effectiveness of doing assignments in an introductory statistics course. Students in one section taught by instructor A received no assignments. Students in another section taught by instructor B, received assignments. The final grade of each student was recorded. A 95% confidence interval for the difference in the mean grades (Section A - Section B) was computed to be -3.5 ± 1.8. This means:
There is evidence that doing assignments improves the average grade since the difference in the population means is less than zero.
There is little evidence that doing assignments improves the average grade since the 95% confidence interval does not cover 0.
There is evidence that doing assignments improves the average grade since the 95% confidence interval does not cover 0.
There is evidence that doing assignments does not improve the average grade since the 95% confidence interval does not cover 0.
There is little evidence that doing assignments does not improve the average grade since the 95% confidence interval does cover 0
1 points
QUESTION 4
A study was conducted to investigate the effectiveness of a new drug for treating Stage 4 AIDS patients. A group of AIDS patients was randomly divided into two groups. One group received the new drug; the other group received a placebo. The difference in mean subsequent survival (those with drugs - those without drugs) was found to be 1.04 years and a 95% confidence interval was found to be 1.04 ± 2.37 years. Based upon this information:
We can conclude that the drug was effective since those taking the drug lived, on average, 1.04 years longer.
We can conclude that the drug was ineffective since those taking the drug lived, on average, 1.04 years less.
We can conclude that there is no evidence the drug was effective since the 95% confidence interval covers zero.
We can conclude that there is evidence the drug was effective since the 95% confidence interval does not cover zero.
We can make no conclusions since we do not know the sample size nor the actual mean survival of each group.
1 points
QUESTION 5
Herbicide A has been used for years in order to kill a particular type of weed, but an experiment is to be conducted in order to see whether a new herbicide, Herbicide B, is more effective than Herbicide A. Herbicide A will continue to be used unless there is sufficient evidence that Herbicide B is more effective. The alternative hypothesis in this problem is that
Herbicide A is more effective than Herbicide B.
Herbicide B is more effective than Herbicide A.
Herbicide A is not more effective than Herbicide B.
Herbicide B is not more effective than Herbicide A.
Herbicides A and B differ in effectiveness.
1 points
QUESTION 6
We wish to test if a new feed increases the mean weight gain compared to an old feed. At the conclusion of the experiment it was found that the new feed gave a 10 kg bigger gain than the old feed. A two-sample t-test with the proper one-sided alternative was done and the resulting p-value was .082. This means:
there is an 8.2% chance the null hypothesis is true.
There was only a 8.2% chance of observing an increase greater than 10 kg (assuming the null hypothesis was true).
There was only an 8.2% chance of observing an increase greater than 10 kg (assuming the null hypothesis was false).
There is an 8.2% chance the alternate hypothesis is true.
There is only an 8.2% chance of getting a 10 kg. increase.
True
False
Explanation / Answer
1) True
Sample size can be different
2) n1 = 24 ,n2 = 27
c) Degree of freedom = smaller of n1-1 and n2-1 = 23
3)
-3.5 ± 1.8.
(-5.3,-1.7)
Since all values are negative, it means score of section B is more.
Hence
c) There is evidence that doing assignments improves the average grade since the 95% confidence interval does not cover 0
4) 1.04 ± 2.37 years.
= (-1.33,3.41)
We can conclude that there is no evidence the drug was effective since the 95% confidence interval covers zero.
5)
Alternate hypothesis
b) Herbicide B is more effective than Herbicide A.
as want to know if a new herbicide, Herbicide B, is more effective than Herbicide A