What is the name given to the 'hypothesis of no difference'?
Null Hypothesis
100
What is the computational formula for a z-test?
z = score - mean / standard deviation
100
A researcher wishes to determine whether serial recall improves with age. She takes a sample of 10 children and measures the same group at age 5 and age 8. Which type of t-test would be suitable for this data?
Correlated Samples T-test
100
Correlation is a definite indicator of causation. True or false?
False
200
What is an independent variable?
The variable manipulated by the experimenter.
200
What is the name given to a statement outlining the precise meaning of a procedure or concept within an experiment.
Operational Definition
200
Which piece of information is known in a z-test but is estimated in a t-test?
Population standard deviation.
200
Which type of t-test has the following degrees of freedom df = n1 + n2 – 2?
Independent Samples T-test
200
Which of the following represents the strongest correlation?
a) 0.88
b) -1.23
c) 1.08
d) -0.97
d) -0.97
300
In a normal distribution, what percentage of scores lie within 1 standard deviation either side of the mean?
68%
300
What is the name given to a group of subjects/participants that do not receive the treatment level of the independent variable and are used as a comparison group to increase validity?
A control group.
300
If z-obtained falls outside the critical range -1.96 < z < +1.96 what would the decision regarding the null hypothesis be?
Reject the null hypothesis.
300
A researcher wants to know if university students sleep more or less than the recommended 8 hours of the general population. She takes a random sample of 15 university students and records how much they’ve slept on average for the past week.
Outline the null and alternative hypotheses for this research.
H0 = 8 OR H0: u students = u population
H1 ≠ 8 OR H1: u students ≠u population
300
_________ is an external variable in a statistical model that correlates with both the dependent variable and the independent variable so that the results obtained do not reflect the actual relationship between the variables under investigation.
Confounding Variable
400
What are the characteristics of ratio data?
The data is measured based on magnitude of difference between data points and the measurement scale has a true zero.
(Category + Order + Magnitude of Difference + Ratio with true zero)
400
Failing to reject the null hypothesis when it is false is known as _______ error.
Type II
400
If the standard deviation is 4, the variance is 16 and the sum of squares is 400, what size is your sample?
25
400
If the population mean is 8, the sample mean is 6, the standard deviation is 2 and the standard error of the mean is 4, what is the t-score?
t = score - mean / standard error
= 6 - 8 / 4
= -0.50
400
______________ indicates the proportion of variability in the dependent variable that can be accounted for by the independent variable.
Coefficient of Determination
r-squared
500
The concept that outlines that as sample size increases, the sample mean will better approximate the population mean and approach normal distribution.
Central Limit Theorem
500
A researcher believes that people taking a performance-enhancing drug will run faster than people without the drug. He has them run 10 metres and records their times. How would the alternative hypothesis be expressed?
H1: μ drug < μ no drug
500
Paul receives a score of 59 on his chemistry exam with a class mean of 63 and standard deviation of 8.
Billy receives a score of 33 on his biology exam with a class mean of 35 and standard deviation of 9.
Which student performed better?
Billy performed better.
Billy
z = 33 - 35 / 9 = -0.22
Paul
z = 59 - 63 / 8 = -0.50
500
Group A:
Sample Size = 15
Variance = 40
Group B:
Sample Size = 25
Variance = 10
What is the pooled variance?