For each research study below, you need to identify the null and alternative hypotheses, What type of stat will you use and JUSTIFY WHY, Identify the IV and DV OR the X and Y. Is it a one tailed or two tailed test?

A medical researcher wants to know if pet ownership increases the probability of living one year after a heart attack. A total of 200 coronary patients were asked if they owned a pet and were followed up one year after a heart attack to see if they were still alive.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

A memory researcher is interested in how atypical actions in an event (e.g., the cash register falling on the floor while your in line at the grocery store) are remembered over time. 50 people participate in a grocery store event and are asked to recall everything that happened immediately afterwards, 1 month later and 6 months later. She records the number of atypical actions recalled each time. Does the recall of atypical information decline over time?

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

Dr. Sims is interested in whether or not her Supplemental instructor is helping students with their work in her research methods class. She accrues the students grades from this semester and compares them to the past 4 years of grades. Unfortunately, she does not know the standard deviation for the past four years of grades.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

A study was conducted to examine the impact of speaking in public on college students. A class of 15 statistics students participated in the study. At the beginning of a lecture the students recorded their systolic blood pressure. During the lecture the instructor called on each student to stand and answer questions about topics in the lecture. After speaking the students once again recorded their blood pressure.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

A random sample of 3rd grade children were placed in a special program to improve their reading ability. After a 10 week intensive program, do they read significantly better than average 3rd grade children, that is, as compared to the national norms? Let's assume that we know both the national norm to be 60 AND its population standard deviation is 3.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

Does the type of movie children are watching make a difference in the amount of snacks they will eat? A group of 50 children were randomly assigned to watch either a cartoon or a live action musical (25 to each). Crackers were available in a bowl, and the investigators compared the number of crackers eaten by children while watching the different kinds of movies.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

In the study described above, the next weekend they took all 50 children and put them into groups based on their weight. Each child in the live action group was weighed and a second child in the same weight category was put in the cartoon group. The number of crackers were now assessed for all children.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?

Dr Nomack believes that Obsessive compulsive disorder can best be treated by using a combination of SSRI's and cognitive therapy. He currently has 1,000 clients diagnosed with this disorder who are being seen in his practices. He has randomly assigned each client into one of the following treatments groups: No therapy; SSRI alone; CBT alone; SSRI and CBT in combination. After a 12-week interim, he then assesses all 1,000 clients on the Big T Obsession and Compulsion rating scale. He expects that those clients who are receiving both SSRI's and CBT will show the fewest symptoms after the treatment phase.

Ho:

Ha:

IV:

DV:

How many tails?

WHAT stat will you use?