Time to Practice – Week Three
Complete both Part A and Part B below.
For the following research questions, create one null hypothesis, one directional research hypothesis, and one non-directional research hypothesis.
What are the effects of attention on out-of-seat classroom behavior?
Students labeled as ADHD-severe will have same out of desk frequency as children not labeled ADHD-Severe.
Severe ADHA kids will be out of desks more than non ADHD severe kids.
ADHD severe kids will be out of desks at different frequency then kids not ADHD severe.
What is the relationship between the quality of a marriage and the quality of the spouses’ relationships with their siblings?
Strong marriages will have low quality of sibling relationship.
Strong marriages will have high quality relationship with siblings.
Strong marriages will have varying quality relationship with siblings.
Provide one research hypothesis and an equation for each of the following topics:
The amount of money spent on food among undergraduate students and undergraduate student-athletes
Hypothesis- There’s a difference between Undergraduate students and Athletes in regards to money spent on food.
Equation- H1: X us ≠Xus-a
H1: Xw≠X b
The effects of Drug A and Drug B on a disease
Hypothesis- Drug A will be more effective positively than Drug B
H1: X da≠X db
The time to complete a task in Method 1 and Method 2
Hypothesis- It will be faster to complete 1 task verus 2
H1: X t1≠X t2
Why does the null hypothesis presume no relationship between variables?
The null hypothesis presumes there is no relationship between variables because null literally means no or none. So a none hypothesis is claiming that there is no relationship or it is not looking for a relationship between the variables. The null hypothesis is a starting point that allows for all possibilities in the absence of other data it is presumed that everything is true.
Create a research hypothesis tested using a one-tailed test and a research hypothesis tested using a two-tailed test.
One-tailed: Ho: Drug A has no effect; Mean of Drug Response time 1.2 seconds
Ha: Drug A lowers Response; Mean of Drug < 1.2 S
Two-Tailed: Ho: Drug A has no effect; Mean response time 1.2 Even without drug
Ha: Drug A has an effect; Mean response 1.2 With drug given.
What does the critical value represent?
The critical value represents a value an individual would assume the test at hand to produce if the null hypothesis were true. It is the statistic a person believes to find.
Given the following information, would your decision be to reject or fail to reject the null hypothesis? Setting the level of significance at .05 for decision making, provide an explanation for your conclusion.
The null hypothesis that there is no relationship between the type of music a person listens to and his crime rate (p< .05).
Null hypothesis is rejected as p value is less than 0.05
The null hypothesis that there is no relationship between the amount of coffee consumption and GPA (p = .62).
P=0.62 which is more than 0.05 or greater we accept Null Hypothesis
The null hypothesis that there is a negative relationship between the number of hours worked and level of job satisfaction (p = .51).
P=0.51 greater than 0.05 Accept null
Why is it harder to find a significant outcome (all other things being equal) when the research hypothesis is being tested at the .01 rather than the .05 level of significance?
When the test I done at the .01 rather than the .05 it produces a much small value set while .05 produces a larger one. This leads to the contradictory data which is quite larger in the research hypothesis and more likely.
Why should we think in terms of “failing to reject” the null rather than just accepting it?
When is it appropriate to use the one-sample z test?
- Because through failing to reject the null hypothesis we are failing in terms of confidence intervals or finding no difference in the value of the confidence interval. This only means that we failed to find a difference and the data may still have differences which means that failing to reject the null just means that we didn’t prove there were differences and does not mean that we have shown that there is no differences.
The one-sample z-test is appropriate when we know the standard deviation in the population. It is used to compare a simple mean to a population mean and determine the likelihood of obtaining a particular mean, so the standard deviation of the population is important. I can be used on any measure that has been collected for an entire population that a person is interested as long as the standard deviation is known.
From Salkind (2011). Copyright © 2012 SAGE. All Rights Reserved. Adapted with permission.
Complete the following questions. Be specific and provide examples when relevant.
Cite any sources consistent with APA guidelines.
|The average raw math achievement score for third graders at a Smith elementary school is 137; third graders statewide score an average of 124 with a standard deviation of 7. Are the Smith third graders better at math than third graders throughout the state? Perform the correct statistical test, applying the eight steps of the hypothesis testing process as demonstrated on pp. 185–187 of Statistics for People Who (Think they) Hate Statistics.
|Null: No difference between 3rd graders at Smith and Statewide 3rd graders. Ha: There is a difference in the 3rd graders at Smith and Statewide 3rd graders. Test Stats: t=(x-mu)/SD*squrt(sample) Null mu=0 In the problem mu=124, SD=7, x=137, sample=100 test of mu=0 vs not=0 N Mean SE Mean 95% CI Z P100 124.000 0.700 (122.628, 125.372) 177.14 0.000Null rejected.
|What is a research question that you would like to answer? Write the null and research hypotheses. Would you use a one- or two-tailed test? Why?
|If the Health department is tasked with finding out rate of Aids transference for the past year is it comparable to average rate of past 50 years. Null: No difference in last year and last 50 years. Ha: There is a difference in last year and last 50 years. Using a two-tailed test because of the Ha would show that it was not equal and the statistical language and lack of SD would mean a two-tail is the best option.
|What do we mean when we say that a statistical result is significant? What is the difference between a statistically significant and a meaningful result? Why is statistical significance important?
|Significant means that there is a rate of certain probability in something. Meaningful results states that the results are valid and statistically significant which means a person rejects the null hypothesis for the Ha. With there being some probable difference between the results we can conclude the null hypothesis isn’t acceptable and should be rejected.
|Describe a Type I error for the previous study that compares third graders’ math achievement. Describe a Type II error for that study.
|A type 1 error happens when the rejection of the null hypothesis happens because there is no difference in the Smith 3rd graders and the statewide 3rd graders. Type 2 error is when the null is accepted and there is no difference in Smith’s 3rd graders and statewide.
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