Key Terms/Definitions
The hypothesis that states there is no effect from the treatment.
What is the null hypothesis?
This formula uses the population standard deviation when calculating the standard error.
What is the z-test?
This test aims to see whether or not a sample is above or below average.
What is a one tailed test?
The variable that represents the probability of making a type 2 error.
What is Beta?
Average heart rate for Americans is 72 beats/minute. A group of 25 individuals participated in an aerobics fitness program to lower their heart rate. After six months the group was evaluated to identify is the program had significantly slowed their heart. The mean heart rate for the group was 69 beats/minute with a standard deviation of 6.5. Calculate the appropriate statistic.
2.3
The number of values that are free to vary without changing the statistic.
What are degrees of freedom?
This formula uses the sample standard deviation when calculating the standard error.
What is the t-test?
This value is the cutoff for claiming a test's results are significant.
What is a critical value?
The variable that represents the probability of making a type 1 error.
What is alpha?
The average score for 18 holes in golf is 90. You’re golf club of 14 students averages 87 with a standard deviation of 7. Calculate the appropriate statistic.
1.6
Regardless of the shape of the population raw scores, if your sample size (N) is larger enough, your sampling distribution of the mean will be normal.
What is the Central Limit Theorem?
Following the assumption that the null hypothesis is true, this formula has you input a zero for your population mean difference.
What is a correlated groups/paired samples t-test?
This table has a different sampling distribution for each sample size.
The larger this variable is, the more statistically powerful our experiment is.
What is Cohen's D?
A manufacturer of running shoes knows that the average lifetime for a particular model of shoes is 15 months. Someone in the research and development division of the shoe company claims to have developed a longer lasting product. This new product was worn by 30 individuals and lasted on average for 17 months. The variability of the original shoe is estimated based on the standard deviation of the new group which is 5.5 months. Calculate the appropriate statistic.
1.99
The probability that you obtained your results has to be less than or equal to this.
What is alpha=0.05?
These formulas include the population mean.
What are the z-test, t-test, and correlated groups t-test?
One sample, twice; Two samples once.
What is correlated groups; independent groups?
This variable is in the denominator of both the single sample z and t tests, and is estimated for the t-test.
What is the standard error of the mean?
A research team wants to investigate the usefulness of relaxation training for reducing levels of anxiety in individuals experiencing stress. They identify 30 people at random from a group of 100 who have "high stress" jobs. The 30 people are divided into two groups. One group acts as the control group - they receive no training. The second group of 15 receive the relaxation training. The subjects in each group are then given an anxiety inventory. The summarized results appear below where higher scores indicate greater anxiety.
x-bar 1= 30
s1= 6.63
n=15
x-bar 2=26
s2=6.2
n=15
1.70669
The bigger the sample, the better the sample mean will estimate the population mean.
The Law of Large Numbers.
This is the only formula that includes the degrees of freedom in the computation.
What is an independent groups t-test?
Our alpha level should we deiced to switch between a one and two tailed test.
What is 0.075?
A special kind of variance for an independent groups t-test, that estimates its corresponding population value.
Twenty participants were given a list of 20 words to process. The 20 participants were randomly assigned to one of two treatment conditions. Half were instructed to count the number of vowels in each word (shallow processing). Half were instructed to judge whether the object described by each word would be useful if one were stranded on a desert island (deep processing). After a brief distractor task, all subjects were given a surprise free recall task. The number of words correctly recalled was recorded for each subject.
Sum of x1= 126
Sum of x21=1618
Sum of x2= 142
Sum of x22= 2040
2.066