Exam 7: Hypothesis Testing With Z Tests

Claire knows the z score for her research hypothesis is -2.05, and her critical values are -1.96 and 1.96 for a p value of 0.05.What should she conclude about her hypothesis given these statistics?

The crowd-sourcing movement in research is:

Use the following to answer questions Study Description: Tail Wagging A New York Times article published on April 24, 2007, reported the research of Dr.Giorgio Vallortigara, a neuroscientist at the University of Trieste, Italy, and his two colleagues.The researchers asked whether a dog wags its tail in a preferred direction in response to positive stimuli and in another direction in response to negative stimuli.To answer their question, they recruited 30 dogs that were family pets.Filming each dog from above, they allowed it to view (through a slat in its cage) three positive stimuli separately, in order of descending positivity: its owner, an unfamiliar human, and a cat.All the dogs responded by wagging their tails to the right.But when the dogs were presented with an unfamiliar, aggressive dog, a negative stimulus, all dogs wagged their tails to the left. -(Study Description: Tail Wagging) Which statement is the research hypothesis for this study?

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Mark studies 16 hours per week.What percent of students are at least as extreme as Mark, in both directions? (Round z score to two decimal places.)

Replication involves conducting:

The critical values for a statistical test mark the value beyond which one can reject the null hypothesis.

The symbol for the null hypothesis is _____ and the symbol for the research hypothesis is _____.

Use the following to answer questions Study Description: Dance Dance Revolution Unnithan, Houser, and Fernhall (2006) were interested in whether playing the game Dance Dance Revolution (DDR) affected the heart rate of overweight adolescents differently than it affected non-overweight adolescents.Twenty-two adolescents, 10 classified as overweight and 12 as not overweight, played DDR for 12 minutes, while the researchers measured each participant's heart rate.On average, the researchers found no difference between the heart rate of the two groups. -(Study Description: Dance Dance Revolution) Which statement is the null hypothesis for this study?

If a researcher wanted to determine whether her results were specific to the sample or context used, she should:

The z table only allows for the calculation of percentiles for positive z values.

If studies fail to replicate:

A single observation can be expressed in a number of ways that all refer to that same observation and the exact same place within the normal curve.These expressions are:

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.The professor tells David he scored at the 76th percentile.How many hours does he study per week? (Round z score to two decimal places.)

Atif has a z score of 0.98 from a converted IQ score.From a z table, the percentage between his score and the mean is 33.65 percent.What percent of people have IQs at or lower than Atif's score?

The z table only allows for the calculation of percentiles for negative z values.

Rose believes there is a positive correlation between watching violence on television and aggressive behavior.What would be her null hypothesis?

When determining the z value for a mean rather than a score, the value is called a standardized z.

In the six steps of hypothesis testing, when are the null and research hypothesis stated in relation to calculating the test statistic?

The _____ level is the probability used to determine the critical values, or cutoffs, in hypothesis testing.

India converts her raw score on a memory scale to a z score and finds that her score corresponds to a z score of -0.92.She knows her score is below the mean.What percent of people scored lower than India on the memory scale?