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100
What is the symbol for the population standard deviation? (Two part question)
Sigma and the symbol for sigma
100
If we had a within-group design, how many standard deviations would need to be calculated and why?
Standard deviation is calculated only once in a within-groups design because you would be calculating the standard deviation of the difference scores
100
If N=10, How many degrees of freedom is there?
9, df=n-1
100
If you have a non-directional hypothesis, do you need to use a one tailed or a two tailed test?
Two tailed
100
When would you use and independent samples t-test?
When calculating between-group comparisons.
200
What formula would you use to calculate an independent samples t-test?
t = (m1-m2)/SDm
200
What is the purpose of a t-test?
To determine if there is a statistical difference between the mean of the two samples you are comparing.
200
When referring to a t test for dependent data, lets say there is four different scores, and the standard deviation of the difference scores is 2.16. What would be the standard error of the mean difference (SmD)?
SmD=1.08
200
For a directional hypothesis, critical z score is closer to the mean. Is this one tailed or two tailed?
One Tailed.
200
When would you use a dependent samples t-test?
When calculating within-group comparisons.
300
What is the formula for the z-statistic?
Z Stat= (m-Population Mean)/SEM
300
What is the critical z-score?
The boundary between what's typical or not.
300
Calculate the t-statistic: m1=5, m2=4, s1=.5, s2=1, n1=10, n2=10
SDm= .27 t= 3.70
300
Let’s say our statistics class conducted an experiment proposing that 75% of the students on campus were going to vote in the upcoming election. After our experiment was complete we found that p=.16. Would we accept the null hypothesis or reject it?
Accept it.
300
What is the relationship between science and statistics?
The scientific method is used to observe, formulate a hypothesis, analyze it, and test it. Statitistics helps determine whether there is an effect or not. A variability is used to see fluctuation or we won't be able to see how reliable the data is.
400
How would you find the value of "t" for a dependent sample t-test?
t= (m1-m2)/SmD
400
To properly use a paired sample t-test, what assumptions must be met?
Interval or ratio scale of measurement, underlying distributions are bell-shaped, homogeneity of variance (similar variability in each sample), and the observations are correlated.
400
When Plymouth State University polled its freshmen and sophomore students about the food in the dining hall. Of the freshmen class 252 replied, the average rating was 7.4/10 with a standard deviation of 2.2. Of the sophomore class 185 replied, the average rating was 6.6/10 with a standard deviation of 3.9. What is the standard error of the difference of the means?
.32
400
Would you use the following degrees of freedom formula for paired-samples t-test or independent samples t-test? df = n1+n2 -2
Independent samples t-test
400
Why do we try to disprove the null hypothesis?
It is much easier to rule something out than to prove something as true.
500
What formula would you use to calculate the Standard Error of the Difference of the Means?
SDM = √(S1^2/n1)+(S2^2/n2)
500
What is the difference between a z-score and a z-statistic?
A z-score is one datum, one raw score and is a descriptive statistic. It measures how far one data point is from the mean. A z-statistic is an inferential statistic, it shows the difference between the sample and population means and is a group of data.
500
Calculate the z-statistic for a sample of 10 people, a sample mean of 5, a population mean of 7, and a population standard deviation of 3
-2.11
500
Your doctor gives you a test to see if you a certain type of cancer. Which is worse: false alarm or a miss?
A miss.
500
Can beliefs be evaluated scientifically? Why or why not?
No, because they are NOT falsifiable.