statistics homework
Define “power” in relation to hypothesis testing.
#2. Alpha (a) is used to measure the error for decisions concerning true null hypotheses. What is beta (ß) error used to measure?
#3. In the following studies, state whether you would use a one-sample t test or a two-independent-sample t test.
1. A study testing whether night-shift workers sleep the recommended 8 hours per day
2. A study measuring differences in attitudes about morality among Democrats and Republicans
3. An experiment measuring differences in brain activity among rats placed on either a continuous or an intermittent reward schedule
Use SPSS and the data file found in syllabus resources (DATA540.SAV) to answer the following questions. Round your answers to the nearest dollar, percentage point, or whole number.
#4. Test the age of the participants (AGE1) against the null hypothesis H0 = 34. Use a one-sample t-test. How would you report the results?
a. t = -1.862, df = 399, p > .05
b. t = -1.862, df = 399, p < .05
c. t = 1.645, df = 399, p > .05
d. t = 1.645, df = 399, p < .05
#5. What is the mean and standard deviation for the Lifestyle score (L)?
a. 31.22, 7.99
b. 36.19, 8.54
c. 30.03, 7.28
d. 55, 13
#6. The first case shown in the data file is a firefighter with a financial Risk-Taking score (R) of 38. What is his Risk-Taking z-score (hint: you will need to find the Risk-Taking mean and standard deviation)?
a. 0.179
b. -0.223
c. 1.342
d. -1.223
#7. Perform independent sample t-tests on the Lifestyle, Dependency, and Risk-Taking scores (L, D, and R) comparing men and women (GENDER1). Use p < .05 as your alpha level and apply a two-tailed test. On each of the three scales, do men or women have a significantly higher score?
a. Lifestyle: Men, Dependency: Women, Risk-Taking: Men.
b. Lifestyle: Not significantly different, Dependency: Women, Risk-Taking: Men
c. Lifestyle: Women, Dependency: Women, Risk-Taking: Men
d. Lifestyle: Men, Dependency: Men, Risk-Taking: Not significantly different
#8. The median US salary is $50,700, according to US Census data. Using a one-sample t-test, test to see if participant income (INC1) is different from the national average. Use a two-tailed test and an alpha level of 5%.
1. Participant income is significantly greater than the national average
2. Participant income is significantly less than the national average
3. Participant income is not significantly different from the national average
4. Participant income cannot be compared to the national average
Statistics Exercise III: Related-sample t; confidence intervals
These weekly exercises provide the opportunity for you to understand and apply statistical methods and analysis. Unless otherwise stated, use 5% (.05) as your alpha level (cutoff for statistical significance).
#1. For each example, state whether the one-sample, two-independent-sample, or related-samples t test is most appropriate. If it is a related-samples t test, indicate whether the test is a repeated-measures design or a matched-pairs design.
A professor tests whether students sitting in the front row score higher on an exam than students sitting in the back row.
A graduate student selects a sample of 25 participants to test whether the average time students attend to a task is greater than 30 minutes.
A researcher matches right-handed and left-handed siblings to test whether right-handed siblings express greater emotional intelligence than left-handed siblings.
A principal at a local school wants to know how much students gain from being in an honors class. He gives students in an honors English class a test prior to the school year and again at the end of the school year to measure how much students learned during the year.
#2.
A random sample of 25 professional basketball players shows a mean height of 6 feet, 5 inches with a 95% confidence interval of 0.4 inches. Explain what this indicates.
If the sample were smaller, would the confidence interval become smaller or larger? Explain.
If you wanted a higher level of confidence (99%) would the confidence interval become smaller or larger? Explain.
Use SPSS and the data file found in syllabus resources (DATA540.SAV) to answer the following questions. Round your answers to the nearest dollar, percentage point, or whole number.
#3. Test to see if there is a significant difference between the age of the participant and the age of the partner. Use a paired-sample t-test and an alpha level of 1%. How would you interpret the results of this test?
a. The partners are significantly older than the participants.
b. The partners are significantly younger than the participants.
c. The age of the participants and partners are not significantly different.
d. Sometimes the partners are older, sometimes the participants are older.
#4. What is the 95% confidence interval for the difference between participant and partner age?
The partner is from .60 to 1.76 years older than the participant
The participant is from .60 to 1.76 years older than the partner
The partner is from 5.88 to 9.45 years older than the participant
The participant is from 5.88 to 9.45 years older than the partner
These weekly exercises provide the opportunity for you to understand and apply statistical methods and analysis. Unless otherwise stated, use 5% (.05) as your alpha level (cutoff for statistical significance).
#1. Which type of ANOVA would you use for each of the studies below?
One-way between subjects (independent groups)
One-way within subjects (repeated measures)
Two-way between subjects
Measure the self-esteem of the same group of college students at the beginning, middle and end of their freshman year.
Compare math skills for three different professional groups: physicians, attorneys and psychologists.
Measure Body Mass Index (BMI) for persons who take Supplement X vs. a placebo and who either exercise regularly or don’t. So there are four groups: 1) Exercise/Take Supplement X, 2) Don’t Exercise/Take Supplement X, 3) Exercise/Take Placebo, 4) Don’t Exercise/Take Placebo
Look at satisfaction with mental health services based on the client’s ethnicity (White, Black, Hispanic, Asian or Other) and how they were greeted on their initial visit (receptionist smiles or does not smile).
