Statistical Tests
Statistical analyses, such as t-tests and F-tests, help us test and draw ___ about ideas and hypotheses. These types of tests are called ___ statistics.
Conclusions; Inferential
John tested his new treatment on 10 individuals. He concluded that the treatment did work and should be marketed to the public. Why should we be weary of his conclusion?
His sample size was very small.
What do we call the process of collection, analysis, interpretation, and presentation of masses of data?
Statistics
Below are the steps of the scientific method. What are the missing steps?
1. Develop research hypothesis
2. Collect data
3. ___
4. Draw a conclusion
5. ___
3. Analyze data
5. Communicate findings
Central tendency and variability are measures that ___ data.
Describe or summarize
Sam is interested in comparing his test scores to his class. He believes he will score significantly higher than his peers. What test would he use to test his belief?
z-test
z-scores tell you the ___
number of standard deviations a score is away from the mean.
What types of studies are able to test causal (or cause-and-effect) relationships between variables?
Experimental studies
To compare the average scores between two distinct groups, what type of figure should you use?
Bar graph
Which hypothesis assumes there is no relationship between variables, that the independent variable has no effect on the dependent variable?
Null hypothesis
Thor believes that parenting style influences level of success a child has as an adult. He compares 4 types of parenting style: authoritarian, authoritative, permissive, and uninvolved. To measure success level, he measured each child's GPA. He compared the average GPA of children from each parenting style. What type of analysis should be conducted?
ANOVA or F-test
The result of the t-test is t(151) = .45, p > .05.
Was there a significant difference and why/why not?
No significant difference because p-value is greater than .05.
Many believe that the color of something can influence one's perception. Some lawyers even go as far as telling their clients to wear certain colors to get a more favorable outcome from the jury or judge. What is the independent and dependent variable for this situation?
Independent variable: Color
Dependent variable: Perception/judgement
Susie believes that the number of siblings one has affects one's personality. There are 4 types of measurements: nominal, ordinal, ratio, interval.
What type of measurement would Susie take to measure the number of siblings one has?
Ratio - true zero exists
What central tendency measure should be reported for skewed data?
Median
Pam believes that having pets can effect one's mental well-being. Pam wants to use a two-sample t-test as her analysis. How can she measure her variables in order to do so?
Need 2 groups, compare average scores
Ex:
Pets - two groups/samples. Pets vs. no pets
Mental well-being - numerical, anxiety on scale of 1-10
The result of an F-test is F(5, 823) = 4.32, p = .04, r2 = .13.
Is there a significant difference between the groups, and what is the size of effect?
Yes, there is a significant difference between the groups. There is a medium size of effect.
In a standard normal distribution, the characteristics include unimodal and bell-shaped. The mode, median, and mean are all ___.
equal/the same.
A statistics is calculated to estimate the ___.
population parameters.
How do we know when we've made either a Type I error or a Type II error?
When follow-up studies contradict our conclusions
Michael wants to study the potential relationship between smoking behavior/habits and social skills. How can he measure both variables to be able to use correlation/regression analysis to test his hypothesis?
Both variables needs to be numerical.
Ex:
-smoking - number of cigarettes smoked
- social skills - number of friends
The result of a correlation/regression analysis for a study measuring the relationship between exercise (X) and resting heart rate (Y) in men is as follows:
r(335) = -.09, p < .01
y = -.20X +85
A. Is there a significant relationship between exercise and resting heart rate?
b. What direction is the relationship between exercise and resting heart rate?
c. What is the predicted resting hear rate for someone whose exercise value is 20?
A. Yes
B. negative relationship
C. 81
Why should we never use the word "prove" in our conclusions?
Proof implies absolute certainty, and that is not achieved because we use probabilities to determine our conclusions
Sample variances are biased, so we need to adjust the formula to be better able to estimate the true population score
The mean is known as the center of the distribution because ___.
Added deviations equal to zero.