(12 pts) The Inventory of Parent and Peer Attachment measures the level of attachment of individuals to their friends. A higher score indicates greater attachment. An education researcher wonders if there is a difference in the IPPA mean scores of students who participate in community service and those that do not. She surveyed 57 students who had done service work and 17 who had not. The sample mean IPPA scores and standard deviations are tabled below. Group Condition n ?̅ s 1 Service 57 104.12 14.68 2 No service 17 96.82 14.26 Does the survey data give significant evidence of a difference in the mean IPPA scores for students in the two community service groups? Address this question with the appropriate procedure. Give all the details.

Problems 6-10: In 2015 about 60% of college students used Twitter. In a recent study of 100 students, 80 now use Twitter. Is this evidence to think the percent has changed? We wish to conduct a hypothesis test with 5% significance.

6) State the null and alternative hypothesis.

7) Find the test statistic and P-value and report those values here:

8) What is the decision and conclusion?

9) Now, construct a 95% confidence interval using the sample of 100 students and 80 saying they use twitter.

10) Does the Confidence Interval support your decision for #8? Why or why not?

11 (Bonus): What type of error could we have made in this anaylsis? (Type 1 or Type 2)

Do people think that diversity in a large population is healthy or damaging? At one college, responses of a randomly selected group of students found that 10 students majoring in behavioral sciences thought diversity healthy and 3 thought it damaging. In the natural sciences, 4 thought diversity healthy and 8 thought it damaging. In the arts, 18 thought diversity healthy and 7 thought it damaging. In the languages, 6 thought diversity healthy and 7 thought it damaging. Finally, in the field of history, 4 students thought diversity healthy and 9 thought it damaging. Do these results suggest that opinions about diversity vary over different majors? (Use the .05 significance level.)

Choose the appropriate test and use the five steps of hypothesis testing!   

1. A university has 10,000 students of which 45% are male and 55% are female. If a class of 30 students is chosen at random from the university population, find the mean and variance of the number of male students. Group of answer choices Mean = 16.5, Variance = 2.7 Mean = 13.5, Variance = 2.7 Mean = 16.5, Variance = 7.4 Mean = 13.5, Variance = 7.4

2. At a particular hospital, 40% of staff are nurse assistants. If 12 staff members are randomly selected, what is the probability that exactly 4 are nurse assistants?

3. Let X be a binomial distribution with n = 20 and p = .4 then the variance is

4.

Find the mean of the distribution shown below.

Do people think that diversity in a large population is healthy or damaging? At one college, responses of a randomly selected group of students found that 10 students majoring in behavioral sciences thought diversity healthy and 3 thought it damaging. In the natural sciences, 4 thought diversity healthy and 8 thought it damaging. In the arts, 18 thought diversity healthy and 7 thought it damaging. In the languages, 6 thought diversity healthy and 7 thought it damaging. Finally, in the field of history, 4 students thought diversity healthy and 9 thought it damaging. Do these results suggest that opinions about diversity vary over different majors? (Use the .05 significance level.)

Choose the appropriate test and use the five steps of hypothesis testing!   

Listed below are grades for Calculus and Precalculus students.

Calculus 95, 87, 55, 88, 79, 80, 86, 91, 93, 68, 91, 79, 73, 81, 90, 72, 84

Precalculus 82, 66, 42, 90, 82, 38, 77, 90, 72, 65, 71, 88, 63, 93, 67, 55, 34, 82, 71

find the mean, standard deviation, sample size, claim, Ho, H1, critical value, test statistic and conclusion

3) Test the claim that the majority of Calculus students are passing the class with a C grade over 70 or better.

4) Test the claim that the majority of Precalculus students are passing the class with a C grade over 70 or better

Assuming that on average college students in the U.S. send 120 text messages per day. A researcher wants to examine if the amount of text messages sent daily by UNC students differs from the national average. The researcher took a sample of 64 UNC students, and finds that the mean number of texts per day is 126 with a standard deviation of 24. Use alpha .05

a) Is this a one-tail or two-tail test? Write appropriate hypotheses and assumptions.
b) Determine the degree of freedom and the critical value for this test.
c) Calculate the standard error.
d) Calculate the test statistics and determine its P-value.
e) State your conclusion by comparing the critical value to the test statistic and by comparing P to alpha.

1. A particular event has a probability of occurrence of p=0.65. Given 12 independent trials, draw the probability distribution and calculate the expected value.
2. A particular event has a probability of occurrence of p=0.65. If each outcome is independent of the last, draw the probability distribution associated with the event not occurring a given number of consecutive times and calculate the expected value.
3. Given the following scenario, determine which distribution (binomial, geometric, hypergeometric) is the most appropriate to model it? Rank the distributions from most appropriate to least appropriate. Explain the reason(s). "1600 students attend BOSS. It is determined that 70% of all BOSS students wear glasses. If groups of 50 students were selected at random, how many of them would be wearing glasses?"

A teacher is comparing the mean study time of his freshmen and senior students. he believes that his senior students spend more time studying per week than his freshmen students and decides to perform a hypotheses test on this belief.

a. suppose the decision of the hypothesis test is to reject the null hypothesis. If in reality freshmen study for a mean of 10 hours per week and seniors study for a mean of 15 hours per week, was an error made? If so, what type?

b. Suppose the decision of the hypothesis test is to fail to reject the null hypothesis. If in reality the freshmen study for a mean of 15 hours per week and seniors study for a mean of 15 hours per week, was an error made? If so, what type?

GPA of the students who are taking Stat 50 class at bcc follows a normal distribution with a mean of 2.87 and a standard deviation of 0.43. If 35 students who are taking Stat 50 are selected, what is the probability that their average GPA is more than 2.97?

A) Not enough information is given to find the answer

B) Almost 0

C) 0.084

D) 0.408

2) GPA of the students who are taking Stat 50 class at bcc follows a normal distribution with a mean of 2.87 and a standard deviation of 0.43. If one student who is taking Stat 50 are selected, what is the probability that his or her average GPA is more than 2.97?

A) Not enough information is given to find the answer

B) 0.408

C) Almost 0

D) 0.084