SWU 321 Final Exam
The appropriate measures of central tendency to use with the variables (a) age and (b) ethnicity are (a)________ & (b)________ respectively.
(a) mean and (b)mode.
The following is a list of Pearson's r coefficients. Which Pearson's r indicates the strongest relationship between variables?
-.54
Identify the mean deviation scores for the following values. The arithmetic mean is 89. [80, 85, 89, 93, 93, 94]
-9, -4, 0, 4, 4, 5
A researcher sets a rejection level at .05. Which of the following p-values would be considered statistically significant? (select all that apply).
.04 .01
You are hired by a high school athletic department to examine the relationship between involvement in team sports and academic achievement among high school students. Please complete steps 1 through 3 of the hypothesis testing process. State the Research Hypothesis. Be sure to indicate whether this is a one-tailed or two-tailed hypothesis. State the Null Hypothesis. Specify the Rejection Level. Be sure to indicate why you chose this rejection level.
1. High school students who are involved in sports achieve higher academic achievements (this is a one-tailed hypothesis). 2. There is no relationship between high school students who are involved in sports and academic achievement. 3. The rejection level is less than .05, I chose this rejection level because any value smaller than this will have a statistical significance and there won't be a sampling error.
You created a new parenting program and you are interested in testing its impact on parenting skills. To do so, you recruit a sample of parents and have them complete a self-report parenting skills scale before participating in the intervention and then after participating in the intervention. The parenting skills scale has multiple items and includes a scale (0-10), so we know the level of measurement for this variable is interval. What type of test can be used to analyze the data?
Dependent t-test
A researcher is interested in determining whether age influences the level of depression experienced by youth. In this study the Children's Depression Inventory (CDI), a standardized measure was used to assess children's depression and children were asked their age. 1. IDENTIFY THE DEPENDENT VARIABLE. 2. IDENTIFY THE INDEPENDENT VARIABLE.
Dependent variable: Children's Depression Inventory Independent variable: Age
An outlier is a typical attribute of a distribution.
False
If a variable is continuous, it must be either a nominal or ordinal variable.
False
Percentile ranks or percentiles indicate the percentage of cases within a group that fall above a particular score
False
The p value is an indicator of rival hypothesis and design flaws.
False
The value of a z-score is always the same as the value of the original raw score.
False
True/False: Weekly hours of working is measured by a question below. This variable is a nominal-level variable. Q.How many hours did you work last week? RESPONSE OPTIONS: 1. 10-15 hours/week 2. 16-20 hours/week 3. 21-25 hours/week 4. 26-30 hours/week 5. 31-35 hours/week 6. 36-40 hours/week 7. Over 41 hours/week
False
(Part 1) Describe, in your own words, what an attribute of a variable is. (Part 2) Using your own example related to your discipline/area of interest, please name two variables that you would be interested in studying and identify the attributes of each variable.
For this question you were to name two variables with associated attributes. Two examples may be: Variable: Field of Social Work; Attributes: Medical, Child Protection, School etc. (Nominal) Variable: Career Satisfaction: Very Unsatisfied, Unsatisfied, Neutral, Satisfied, Very Satisfied (Ordinal)
For what do we use z-scores?
In order to standardize scores from two or more different normal distributions so that we may compare the scores.
You are interested in comparing differences in empathy between male and female middle school students. You have collected data from a sample of middle school students and asked them to complete a survey that measures their empathy. The level of measurement for the empathy variable is interval. What type of test can be used to analyze the data in order to compare male vs. female empathy?
Independent t-test
Which of the following pairs of variables (attributes listed in parentheses) could be analyzed using a chi-square analysis? [hint: consider the level of measurement for each variable]
Marital Status (Single, Married) & Type of Treatment (Individual, Group)
A researcher is interested in racial disparities related to the likelihood of being arrested during a police traffic stop. Please identify the level of measurement for a variable measuring the race of a driver (i.e., White, American Indian, African American, Hispanic, Multiracial, Other).
Nominal
Which of the following is NOT an alternative explanation for relationships within samples?
Null Hypothesis
A researcher is interested in whether job satisfaction varies based on rank of police officers in the Phoenix Police Department. What level of measurement is the variable police officer rank (cadet, officer, sergeant, lieutenant, chief of police)?
Ordinal
When is it necessary to run a post hoc test?
Post hoc tests are required whenever you run a simple ANOVA.
The relationship between job performance and job satisfaction can be explained by a third variable such as age, skill level, or supervisory structure. This is an example of ______________.
Rival hypothesis
A client satisfaction scale has a population mean of 50 and a population standard deviation of 6. In a sample of 100 Latino parents, the average score was 55 on the client satisfaction scale. Please calculate the standard error of the mean. Be sure to show your work.
SE of M= + =.6 SD=6 Square root of sample is 10. 6/10 is .60
A scattergram or scatterplot shows:
Scores (or attributes) on one variable plotted against scores (or attributes) on a second variable.
You are interested in comparing clients' perceptions of social workers by type of treatment (support group, individual therapy, and psychoeducation). You have collected data from clients at a local agency and asked them to complete a survey that measures their perceptions toward social workers. The level of measurement for the perceptions toward social workers variable is interval. What type of test can be used to analyze the data?
Simple ANOVA
Which of the following pairs of variables (attributes listed in parentheses) can be analyzed using a correlation analysis? [hint: consider the level of measurement]
Social Support (measured with a multi-item likert scale) & Life Satisfaction (measured with a multi-item likert scale)
A researcher sets a rejection level at .05. The p-value associated with the statistical test was .09. Which of the following conclusions can be made based on this information.
The hypothesized relationship between variables is NOT statistically significant
A researcher sets a rejection level at .05. The p-value associated with the statistical test was .07. Which of the following conclusions is accurate?
The researcher should fail to reject the null hypothesis
A researcher sets a rejection level at .05. The p-value associated with the statistical test was .01. Which of the following conclusions is accurate?
The researcher should reject the null hypothesis
If a test is valid, what does this mean?
The test measures what it claims to measure.
If a test is reliable, what does this mean?
The test will give consistent results.
Which of the following is a two-tailed hypothesis?
There is a relationship between the number of violent offenses and level of empathy
What is the null form of this research hypothesis:There is a relationship between self-esteem and depression among LGBT youth
There is no relationship between self-esteem and depression among LGBT youth
A frequency distribution can be used to answer questions about the demographics of a target population.
True
The following is a stem and leaf plot for miles driven to work for a sample of social workers. 1 2 2 3 4 5 6 2 1 2 3 4 5 6 3 0 0 0 3 4 5 4 1 2 5 0 3 6 7 Answer the following questions: The sample size is 23. (True or False) Three individuals drive 30 miles to work. (True or False)
True/True
Which of the following describes the variable requirements to conduct a correlation analysis?
Two variables at the interval/ratio level.
A researcher runs a statistical test and determines that there is no statistically significant relationship between variables and fails to reject the null hypothesis. In reality, there is a true relationship between variables. This is an example of __________
Type II Error
Susan is taking an art history class and a biology class. She received a 31 on her first art history exam (Class Mean = 27; SD = 2) and a 59 on her first biology exam (Class Mean = 55; SD= 3). Susan is eager to compare her relative performance in each class. How can z-scores help Susan compare her grades in these two classes? Compute z-scores for both exams. In which class is Susan doing better? [Please show your calculations] Susan's friend Brian from art history class says that he scored exactly 3 standard deviations above the mean on their first exam. Did Brian do better or worse than Susan on this exam?
1. Susan can compare her grades by finding the z score of both and comparing them. Her raw scores will not tell her much if she wants to compare them because they are graded differently. 2. Her z core for history was 2 and her z score for biology was 1.33. This means that she is doing better in her history class because she is 2 standard deviation units above the mean in history rather than 1.33 in biology. I calculated this by subtracting her raw score from the mean and dividing it by the standard deviation. 3. If Brian had a score of 3 above the mean on the exam, Brian received a higher score than Susan. He is one standard deviation unit above her score of 2
A medical social worker is interested in examining the relationship between patients who receive social support by family members (yes/no) and the patients' outcome (failure/success). She collected data over a period of a month (N=100). A chi square analysis revealed the following: χ2= 5.65, df = ?, p = .01. 1. Was a chi-square analysis appropriate to analyze these variables? How do you know? 2. Calculate the degrees of freedom for this analysis (show your work). 3. Is the relationship between social support and patients' outcome statistically significant (use the traditional rejection level)? How do you know?
1. The chi-square was appropriate to analyze these variables because they are both at the nominal level. 2. Each of the two variables have 2 attributes. Df = (r-1)(c-1) = (2-1)(2-1) = 1 3. The relationship between the two variables is statistically significant. Because the p-value is less than .05.
Answer the following questions about this Pearson's r correlation. r = .56, p = .03 Is the correlation statistically significant? How do you know? Provide an example of two variables that could be represented by this correlation [consider level of measurement]. Describe the relationship between the variables that you provided in the previous question (i.e., what happens to one variable as the other increases)? How do you know?
1. The relationship is statistically significant because p=.03 which is less than .05. 2. The two variables I would consider would be at an interval/ratio level of measurement, suppose students are attending college fairs, the number of college fairs they attend (1,2,3,4...) correlates with the number of colleges they've applied to (1,2,3,4....). The more fairs they attend, the more colleges they apply to. 3. As college fair attendance increases, college applications increase.
You received an 88 on an exam. The class mean was 80 (SD = 4). Convert your raw score into a z-score.
2
A researcher was interested in the relationship between two variables: emotional intelligence (measured on a multi-item likert scale) and income. They found that the coefficient of determination (r2) was .32. What is the correct interpretation of the coefficient of determination (r2)
32% of the variation in emotional intelligence is related to the variation in income.
A local program is providing services for LGBT youth. The social worker is writing up the evaluation of the program. She is describing the sample. The average age was 13.5. The variance was 16. What was the standard deviation?
4
Identify the median for the following distribution. 1 2 2 3 4 4 5 5 5 6 6 6
4.5
The degrees of freedom for a 3 x 4 cross-tabulation table will always be:
6
In a normal distribution, approximately what percentage of scores lie within 3 standard deviations of the mean.
99.7
A parametric test is___________________
A statistical test that has more assumptions than a nonparametric test.
As a researcher, you want to compare the 95% confidence intervals of client satisfaction scores from two agencies. You were surprised to notice that the mean scores for both samples were equal (8.5 on a 10-point scale). However, the standard errors differed: the standard error for Agency A was .75 and the standard error for Agency B was .50. Given this information, which confidence interval do expect to be wider?
Agency A's confidence interval will be wider.
Which graph can be used to display the distribution of a nominal level variable?
All of the above
You read a research study that states that the researchers found a significant negative correlation between self-esteem and aggression. Which of the following describes the relationship between these variables in this study?
As self-esteem increases, aggression decreases.
A middle school teacher believes that her female students are discouraged in certain academic subjects and therefore have more negative attitudes toward Science, Technology, Engineering, Math (STEM) disciplines. She decides to conduct a study to test the hypothesis that gender predicts negative attitudes toward STEM disciplines. Which of the following correctly identifies the independent and dependent variables?
Attitude toward STEM is the dependent variable; gender is the independent variable
Why is the sampling distribution referred to as a "theoretical distribution"?
Because, in practice, it is impossible to draw an infinite number of samples from a population.
You are conducting a study on the impact of discrimination on parenting among a sample of Latino and African American parents. You decide that you need to collect demographic information. Describe two demographic variables that you would like to collect, name the attributes of each variable, and describe the appropriate measure of central tendency for each. Your response can be formatted such as the following: VARIABLE 1, ATTRIBUTES FOR VARIABLE 1, MEASURE OF CENTRAL TENDENCY; VARIABLE 2, ATTRIBUTES FOR VARIABLE 2, MEASURE OF CENTRAL TENDENCY
Variable 1: Growing up in your Latino or African American household, did you witness your parents being discriminated against? Attributes for variable 1: Yes/No. Measure of central tendency: Mode, there is no real distance between yes and no. And from that data collected we could see if more people answered yes rather than no. Variable 2: How many times did you notice a change in your parent's behavior after they were discriminated against? Attribute: 0,1,2,3,4,5,6 or more. Measure of central tendency: I would choose median because it is an ongoing or open distribution and there might be someone who noticed 10+ times and that might mess with the distribution.
Suppose you read a research article that reported the results of a chi square analysis examining the relationship between treatment success (attributes = "yes" or "no") and history of substance abuse (attributes = "yes" or "no"). The article included the following results in the note on the contingency table: X2 = 3.376, df = 1, p = .015. Which of the following are accurate interpretations of these results? (SELECT TWO CORRECT ANSWERS)
We can reject the null hypothesis The association between treatment success and history of substance use is statistically significant
Which of the following statement(s) about the standard error of the mean is (are) true? (select all that apply)
We must approximate the standard error of the mean because we never have information on the sampling distribution. The standard error of the mean is the standard deviation of the sampling distribution.
Which of the following describes a Type I error?
When we reject the null hypothesis and conclude that there is a significant relationship, when in reality, the variables are not related
Which of the following is a general requirement of parametric tests?
all the above
Which of the following requirements must be met in order to use a t-test or ANOVA?
an interval or ratio dependent variable
A researcher wants to determine if there is a relationship between media outlet (social media, newspapers, and radio) and interest in media by population group (youth, young adults, and older adults). What type of statistical test should be used?
chi
What type of frequency distribution would tell us at which percentile we scored on this statistics quiz?
cumulative percentage frequency distribution
A researcher is studying depression among older adults. She used Beck's Depression Inventory (BDI) to assess depression among the sample. Before completing her statistical analysis, she wants to get an idea of what the distribution looks like. What graph could she use?
d. b and c
A chi square analysis is a type of univariate analysis.
false
Chi-square requires that each variable is measured at the interval or ratio level of measurement.
false
In a normal distribution, the mean is always greater than the median.
false
Sampling error is the natural tendency of any sample, especially a small one, to be just like the population from which it was drawn.
false
The smaller the cross-tabulation table, the more likely it is to have a large chi-square value.
false
The standard rejection level in social science is .10.
false
You are a researcher who is interested in social relationships among college students. You are creating a survey that will be distributed on ASU's campus. Please answer the following questions: 1) Give an example of a survey question (variable) that you might want to include on the social relationships survey. Be specific about what the variable is from the research question. 2) Describe the attributes of the variable from question 1? 3) What level of measurement is the variable from question 1? 4) Which type of GRAPH would be appropriate to illustrate the frequency of the variable from question 1?
have you been infected with covid this past year would have attributes of yes/no, not information about how social someone has been. For example: Variable 1: Have you been infected with covid in the last 12 months? (Infection) Attributes: Yes/No Variable 2: How social do you consider yourself? (social) Attributes: 0, 1, 2, 3, 4, (0 being not social, 4 being very social)
A child welfare researcher is interested in looking at what characteristics are associated with reunification (the return of a foster child to parent(s)). One variable included in the dataset is number of days until reunification (5 indicates 5 days between removal and reunification, 24 indicates 24 days between removal and reunification, etc.). What level of measurement is this variable?
interval/ratio
In a dataset you are working with, you are interested in describing a variable that consists of the Adverse Childhood Experiences scale. This scale is multi-item and has Likert responses, so you know that you can treat it as an interval level variable. You look at a frequency distribution and the variable is highly positively skewed (fewer people reported many adverse childhood experiences). Which measure of central tendency would be appropriate to describe this variable?
median
When a distribution is skewed, which measure of central tendency is most accurate?
median
A local agency is collecting demographic information from the participants of their Healthy Families program. One of the questions they asked is their children's gender. WHAT IS THE LEVEL OF MEASUREMENT FOR GENDER?
nominal
A variable at the ________ level of measurement CANNOT be re-organized into an array?
nominal
If we conduct a statistical test and the test statistic falls within the rejection region, what is our conclusion?
reject null hypothesis
Previous research suggests that individuals who exercise experience lower levels of stress. You want to test this relationship in a sample of social workers. You follow the required steps in the hypothesis testing process and write the following: "It is hypothesized that social workers who exercise experience lower levels of stress." Which type of hypothesis is this?
research hypothesis
Previous research suggests that individuals who get 7 or more hours of sleep per night experience lower levels of stress. You want to test this relationship in a sample of social workers. You follow the required steps in the hypothesis testing process and write the following: "It is hypothesized that social workers who get 7 or more hours of sleep per night experience lower levels of stress." Which type of hypothesis is this?
research hypothesis
A researcher is analyzing a dataset. She decides to use a particular test that she has used hundreds of times before. When checking the assumptions, she finds that she has violated several important assumptions. Rather than using a more robust test, she decides to move forward with the statistical test that she is familiar with. This scenario is an example of which of the following?
rule of instrument
For t-tests, "degrees of freedom" are a function of:
sample size
The square root of the variance equals the...
standard deviation
The "fishing" approach to data analysis refers to:
the calculation of a large number of t-tests using a single dependent variable and a long list of dichotomous independent variables.
Chi-square is a statistical test of association between variables that compares:
the expected frequencies and observed frequencies
The following data presents the number of diabetes cases among youth over the course of several years. The following distribution is positively skewed. 1, 1, 1, 2, 2, 3, 5, 8, 12, 17
true
