Question

Hello if someone could help me with this multi part probably for the statistics? Thank you!

Question 32q: A researcher is comparing two different weight-loss drugs. She splits her study participants into two halves randomly; every day for a month, one half (Group 1) takes Drug 1, and the other half (Group 2) takes Drug 2. She measures the total weight loss, in pounds, of each participant.

A) Total Weight Loss of Each Participant at the end of the study is (time series data or cross sectional data)

B) Which of the following are true about this data set? (Select all that apply.)

a) Group membership (Group 1 or 2) is a quantitative variable. b) Group membership (Group 1 or 2) is a categorical variable. c) Weight loss is a quantitative variable. d) Weight loss is a categorical variable.

C) The researcher finds that the standard deviation of weight loss in Group 1 is higher than the standard deviation of weight loss in Group 2. This means that in the sample data,

a) Drug 1 provides more consistent weight loss than Drug 2. b) Drug 1 provides less consistent weight loss than Drug 2. c) Drug 1 provides more weight loss than Drug 2, on average. d) Drug 1 provides less weight loss than Drug 2, on average.

D) Nick was a participant in Group 1, so he received Drug 1. The z-score for his weight loss was 2, which means that

a)lost 2 pounds b) His weight loss was 2 standard deviations above the average group participant c)he loss 2 more pounds than the average group 1 participant

E) The researcher decides to run a hypothesis test to test the hypothesis that Drug 1 had no effect, on average. The appropriate test would be a

a)one sample test for a mean b) two sample test of means c)paired test of means d) one sample test for a proportion

F) What is the null hypothesis

a) u1=0 b) u1>0 c) u1<0 d) u1 not equal to 0

G) What is the alternative hypothesis

a) u1=o b) u1>0 c) u1<0 d) u1 not equal to 0

H)

The researcher then changes her mind and decides to run a hypothesis test to compare the means of the two groups. (The remainder of the questions concern this new hypothesis test.)

The appropriate test would be a

a)one sample test for a mean b) two sample test of means c)paired test of means d) one sample test for a proportion

I) What is the null hypothesis

a) u1=0 b) u1>0 c) u1<0 d) u1 not equal to 0

J) What is the alternative hypothesis

a) u1=o b) u1>0 c) u1<0 d) u1 not equal to 0

K) Suppose she finds that the sample mean in Group 1 is 5.40 pounds, while the sample mean in Group 2 is 2.02 pounds. She then determines that the p-value is 0.01. Assuming $LaTeX: \alpha=.05$ α=.05α=.05, she should

A)reject null hypothesis b) fail to reject null hypothesis c)neither

L) Based on the information above, what should she conclude?

a) There is a statistically significant difference in weight loss between the groups B) There is not a statistically significant difference in weight loss between the groups. c) Not possible to make conclusions

M) Recall that the sample mean in Group 1 is 5.40 pounds, while the sample mean in Group 2 is 2.02 pounds. Which of the following could be a 95% confidence interval for the population mean of Group 1?

a) 3.55-7.25 b) 41.14-10.20 c) .1-5.55 d) 4.02 -11.56

N) A 95% confidence interval for the population mean of Group 2 is [0.36, 4.01]. What is the correct interpretation of this interval?

a)We are 95% confident that the expected weight loss resulting from taking a placebo (sugar pill) is between 0.36 and 4.01 pounds. b)There is a 95% chance that the expected weight loss that results from taking a placebo (sugar pill) is between 0.36 and 4.01 pounds. c)95% of participants in the placebo condition of the study lost between 0.36 and 0.41 pounds. d)95% of the time, there is at least a 36% chance that you will lose weight by taking a placebo (sugar pill).

O) Based on the confidence interval above, which of the following could be a 99% confidence interval for the population mean of Group 2?

a) -.61-4.65 b) .36-3.68 c) .83-3.31 d) 0-2.02

P) If the researcher is interested in getting a better estimate (a narrower confidence interval) for Group 1, what could she do?

a) Use larger samples b) Use smaller samples c) use z test not t test d) change the standard error

Q) The researcher then decides to repeat the study with two new samples, and finds that p = 0.02. The difference between the p-value for this study and the last one is due to the fact that

a) an error must have been made in either the first or second study. b)an error must have been made in either the first or second study. c) p-values will always increase when you repeat a study.

Answer 1

Answers

A) Total Weight Loss of Each Participant at the end of the study is time series data. [because is gives daily data over a time period of one month.]

B) True statements are:

b) Group membership (Group 1 or 2) is a categorical variable. [because it only classifies and does not measure or count]

c) Weight loss is a quantitative variable. [because weight loss can be measured]

C) The standard deviation of weight loss in Group 1 is higher than the standard deviation of weight loss in Group 2 means that in the sample data,

b) Drug 1 provides less consistent weight loss than Drug 2. [more the standard deviation less the consistency]

D) The z-score of 2 means that

b) His weight loss was 2 standard deviations above the average group participant [Z = (x - µ)/σ]

E) The appropriate test would be a

a) one sample test for a mean [concern is about on e group only and it clearly says ‘on average’]

F) What is the null hypothesis

a) u1=0 [it should be µ₁ = 0 meaning the average weight loss is nil]

G) The alternative hypothesis

d) u1 not equal to 0 [it should be µ₁ ≠ 0 meaning the average weight loss is not nil]

H) To compare the means of the two groups, the appropriate test would be a

b) two sample test of means

I) The null hypothesis

None of the given options fits. The answer is: µ₁ = µ₂

J) What is the alternative hypothesis

Again, none of the given options fits. The answer is: µ₁ ≠ µ₂

K)

a) reject null hypothesis [because p-value < alpha]

L) She conclude that

a) There is a statistically significant difference in weight loss between the groups

M) 95% confidence interval for the population mean of Group 1

a) 3.55-7.25 [because average of lower bound and upper bound must equal the sample mean]

N) 95% confidence interval for the population mean of Group 2 is [0.36, 4.01] =>

a)We are 95% confident that the expected weight loss resulting from taking a placebo (sugar pill) is between 0.36 and 4.01 pounds.

O) A 99% confidence interval for the population mean of Group 2?

a) -.61-4.65 [99% confidence interval must be wider than the 95% confidence interval ]

P) For getting a better estimate a narrower confidence interval

a) Use larger samples

Q) The difference between the p-value for this study and the last one is due to the fact that

a) an error must have been made in either the first or second study.

DONE