Formuals
Quick Math
Hypothesis Testing
Probability & Z-scores
Paired vs Independent t-tests
100
•The standard deviation for the dist. of sample means is called the ______________
standard error of M
100
If you have an x-value of 45, M= 40 and a s=5, what is the corresponding z-score?
1
100
If t-calc is greater than t-crit, what is our decision for our hypothesis? And is there an effect?
Reject the null hypothesis, there is an effect
100
A raffle has 3 possible prizes: TV, iPhone, and gift card. There is 1 TV winner, 3 iPhone winners, and 10 gift card winners.
If you randomly select one prize, what is the probability that it will be a gift card?
10/14 = .714 or 71.4%
100
Describe the groups for independent vs paired t-tests
Independent- b/w subjects
Dependent- w/in subjects
200
What is the formula for Degrees of Freedom for an Independent T-Test?
Df= df1+df2
200
How many participants are in an independent measures study with a df=24
26
200
What are the One Sample T-test hypotheses?
H0: μ = 0
H1: μ ≠ 0
200
What is the difference between a sample mean and an X-value? In other words, how do you know which equation to use?
An X-value is an individual score on a normal distribution.
A sample mean is the mean calculated for a sample on a distribution of sample means.
200
Calculate the repeated measures t-statistic:
Standard error of the mean difference = 3
MD = 4.5
n = 5
t-calculated = 1.5
t-critical = 2.776
Decision = fail to reject the null
300
What is the formula for Pooled Variance? And for which type of test do you use it for?
(SS1 + SS2)/df1 + df2
Independent t
300
What kind of decision will you make if you get a t-statistic of 1.5 for a repeated measures test with a sample size of n=8 ?
fail to reject the null hypo
300
What is a Type I Error? What is a Type II Error? Which is worse to have?
False positive ; False negative ; Type I Error
300
Which equation should you use?
Scores on a happiness inventory for the general population have a μ = 35 and σ = 10. If a random sample of n = 25 scores is collected, what is the probability that M >40?
Sample mean: x-μ/σ
300
Calculate the independent measures t-statistic:
Pooled variance = 202.5
M1 = 12
n1 = 5
M2 = 1.5
n2 = 5
t-calculated = 1.167
t-critical = 2.306
Decision: fail to reject the null hypothesis
400
What is the formula for Estimated Standard Error? And for which type of test do you use it for? What is that formula for this test?
sample standard deviation/sqr root of n
one sample t
(Mean-mu)/Sm
400
Calculate standard error of the mean for a sample of (n=9) people and a standard deviation of 27
standard error of the mean = 9
400
What are the Independent Measures T-test hypotheses?
H0: μ0 - μ1 = 0
H1: μ0 - μ1 ≠ 0
400
Which equation should you use?
Scores on a happiness inventory for the general population have a μ = 35 and σ = 10. If you had a score of 40, what percentage of people did you score better than?
X-value: z= x-m/ s
400
What was the calculated t-value?
Should the research reject or fail to reject the null hypothesis?
-2.845; Reject the null hypothesis
500
What is the formula for Standard Error of the Mean Difference? And for which type of test do you use it for?
Radical (sample variance/n)
Paired t
500
For a repeated measures (or paired t-test) if your mean difference is 8, and the standard error of the mean difference is 3, what is your t-calc?
t=2.67
500
What are the Paired (Repeated Measures) T-test hypotheses?
H0: μD = 0
H1: μD ≠ 0
500
In chemistry class Jordan gets a 72 on his test. The class average was 76.
Which distribution would say that Jordan's test is better?
s=2 or s=4?
s=4
500
What is the total sample size for this study?
What is the calculated t-value?
Should the researcher reject or fail to reject the null hypothesis?
13; 2.368; Reject the null hypothesis