Exam 10: Hypothesis Testing, Effect Size, and and Confidence Intervals: Two-Sample Designs

According to your text is the reason for doing an experiment.

p > .05 means that the

The restriction that is built into the calculation of the standard error of the mean, the restriction that causes df to be N - 1, is that

Identify the design of each experiment below as paired samples or independent samples. In each case give the df. -Ten students compared the legibility of headlines. In one condition the headlines were all in CAPITALS. In the other condition the first letters were capitalized. Each student judged on a scale of 1-10. Five judged the all capitals headline; five judged the first letter only capitalized.

An experimenter randomly divided a group of volunteers into two groups. One group fasted for 24 hours and the other for 48 hours. One person in the 24-hour group dropped out of the study. Scores below represent the number of ounces of Yummi (Very Vanilla) consumed during the first 10 minutes after the fast. Perform a t test, calculate d, and write a sentence summary of your results. 24 hours 48 hours 26 18 35 24 23 16 30 17 14

If the t distribution is to produce an accurate probability figure, which of the following must be true?

The logic of null hypothesis statistical testing (NHST) is to

Data Set 10-8: Drugs that reduce emotionality make big money for drug companies. These drugs undergo extensive testing, some of which is done with animals. One common test of emotionality in rats is the number of fecal boluses that are dropped when an animal is left for 10 minutes in an open field (a 4' x 4' space). Greater emotionality is indicated by more boluses. Imagine that two drugs, aloe and vera were compared. Five rats were given aloe and five were given vera. The numbers below represent the number of boluses dropped in the open field. Aloe Vera 4 2 12 9 7 6 10 7 6 4 -The experimenter described in Data Set 10-8 is an example of

Data Set 10-6: Drugs used in treating schizophrenia all block the reception of dopamine by neurons. (Dopamine is a neurotransmitter, which, when released by the axons of one nerve, inhibits the firing of the next nerve.) This fact led to the idea that schizophrenia occurs when too much dopamine is produced. Suppose the following data on dopamine production were obtained. Schizophrenics Control Group 42 33 31 27 29 18 -The standard error of the difference for Data Set 10-6 is

To capture the size of the difference between two population means, your textbook used an effect size index.

To capture the size of the difference between two population means, your textbook used confidence intervals.

Identify the design of each experiment below as paired samples or independent samples. In each case give the df. -On the basis of Critical Reading SAT scores, each male was matched with a female. Then the math SAT scores were found and the mean for the 18 males was compared to the mean of the 18 females.

The formula for power is 1 - $\mu$ .

The actual amount of difference between the two populations that the samples are from is most closely associated with

Identify the design of each experiment below as paired samples or independent samples. In each case give the df. -A dozen planaria were fed a stew made from worms that had been previously trained. A second dozen worm's stew was made from naive worms. Each of the two dozen worms then learned a T-maze.

The null hypothesis is a statement about

p < .01 means that the

Data Set 10-5: This experiment is modeled after part of the data needed to demonstrate the Hawthorne Effect. Four assembly-line workers, who normally had two coffee breaks and an hour for lunch, participated in a week-long experiment in which they gave up both coffee breaks and half their lunch hour. Productivity (units produced per hour) for these four was measured under both conditions and is shown below. Productivity/hour Leisurely Schedule Rushed Schedule 6 6 3 5 4 5 5 6 -The t value for Data Set 10-5 is

The numerator of an independent-samples t test is a standard error of a difference.

Indicate whether each design below is independent samples or paired samples and where possible, give the degrees of freedom. -A researcher compared the number of aggressive encounters among 12 children playing with parts of toys to the number among 12 children playing with whole toys.