Investigators performed a randomized experiment in which 414 juvenile delinquents were randomly assigned to either multisystemic therapy (MST) or just probation (control group). Of the 218 assigned to therapy, 92 had criminal convictions within 12 months. Of the 196 in the control group, 75 had criminal convictions within 12 months. Determine whether the therapy caused significantly fewer arrests at a 0.10 significance level. Start by comparing the sample percentages. Find and compare the sample percentages that were arrested for these two groups. The percentage of arrests for people who received MST was (Type an integer or decimal rounded to two decimal places as needed.) The percentage of arrests for people who received probation was ☐ %. (Type an integer or decimal rounded to two decimal places as needed.). The arrest rate was greater for people in the group. Let p represent the population proportion for people who are arrested after having received the treatment and let p2 represent the population proportion of people who are arrested after having not received the treatment. Write the hypotheses for the test. Ho Ha Find the test statistic for this test. z= (Round to two decimal places as needed.) Find the test statistic for this test. Z= (Round to two decimal places as needed.) Find the p-value for this test. p-value = (Round to three decimal places as needed.) What is the conclusion for this test? Use a significance level of 0.10. the null hypothesis. The arrest rate for the people who received MST significantly lower than the arrest rate for the control group.

Colorectal surgery is associated with a high rate of surgical site infection (SSI). Complications arising from SSI significantly increase an individual's length of hospital stay, reduce quality of life, and can also lead to additional health care needs. Outcomes of 2,919 colorectal surgeries were collected for research, including age and whether an individual developed a surgical site infection. Medical researchers would like to use this sample data to learn about health outcomes for colorectal surgery. One question medical researchers were hoping to answer is whether the difference in the ages of colorectal surgery patients who develop SSI and those who do not is too great to have resulted from sampling error alone. Perform a two-sample t-test for comparing two population means to answer this question.

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?

Acne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.

A survey of 1031 adults in a college asked whether they liked chocolate or strawberry ice cream more. Of those surveyed, 536 said they prefer chocolate. Determine and interpret the sample proportion. At the 5% significance level, does the data provide sufficient evidence to conclude that a majority of students in the college prefer chocolate ice cream?

Statistics Question

In the previous year, 40% of women over the age of fifty had regularly scheduled mammograms. Following last year's test, a campaign was initiated to encourage women to be tested regularly. This year, a cancer research group surveys a random sample of 450 women, and 195 respond affirmatively. With a 5% significance level, test to see if the campaign was effective.

A random sample of 1100 potential voters was randomly divided into 2 groups. Group 1:  500 potential voters; no registration reminders sent; 248 registered to vote Group 2:  600 potential voters; registration reminders sent; 332 registered to vote   Do these data support the claim that the proportion of voters who registered was greater in the group that received reminders than in the group that did not?  Use a 1% level of significance.

A study tested the effects of 4 different dosages of a new antidepressant on reducing depressive symptoms in one group of depressed participants. The order of the four dosages was counterbalanced across participants. Which statistical test should be used? Select one: a. One-way between subjects ANOVA b. One-way repeated measures ANOVA c. Two-way between subjects ANOVA Incorrect d. None of these options

In the US, 45.9% of all people have type O blood, 39.7% have type A blood, 11.2% have type B blood and 3.2% have type AB blood. A researcher wants to see if the distribution of blood type is different for millionaires. The table below shows the results of a random sample of 569 millionaires. What can be concluded at the significant level of a = 0.01.   The test-statistic for this data =   The p-value for this sample =