PSY 302 FINAL
If the mean height is 66 inches, with standard deviation of 3.9, what is the approximate probability that a randomly chosen person will be taller than 70 inches?
16% (look at normal distibution table)
Given: Number of participants = 218 Number of groups = 4 SSb = 58 SSw = 160 What is the value of mean squares between? Round to two decimal points
19.33 MSb= SSb / dfb 1. find DFb= # of groups- 1 2. 58 / 3= 19.33
Given population sum of squares SS = 300, and population size of 48, what is the population standard deviation (σ)? Round your answer to two decimal places.
2.5 population standard deviation: square root of SS/N square root of 300/48= 2.5
In one-way, between-subjects ANOVA, the SS-within was 77 and SS-between was 21. What is the percent of total variability accounted for by the effect of treatment? Give your answer in whole percent (%)
21
If the mean IQ is 100 with SD = 15, what is the approximate probability that a randomly chosen sample of 25 people will have a mean IQ greater than 110?
less than .1% HOW TO SOLVE?
In a χ2test of independence, the __________ hypothesis states that the probabilities of one variable do not depend on the value of another variable.
null
The difference between simple and multiple regression is
number of predictors
what scale of measurement is: socioeconomic status (lower, middle, upper)
ordinal
Sometimes, the dependent variable is also referred to as the ________________.
outcome variable
If alpha = .01, we retain the null hypothesis when...
p > .01
You are interested to know if the number of syllables influences memory for words. You get 12 subjects and ask them to memorize 50 words. Twenty-five of the words are one-syllable words, and 25 are three-syllable words. You find that subjects remember an average of 15 of the single-syllable words and 8 of the three-syllable words. Which statistical test you would use to answer the research question and/or analyze the data described?
paired-samples t-test
The mean of the sampling distribution of means is equal to the ___________________. The standard deviation of the sampling distribution of means is called the _________________.
population mean; standard error
If the correlation coefficient R between two variables is ______________, it is expected that the slope of the regression line will be ______________.
positive; positive
Eta squared is an effect size that refers to the proportion of variability in the outcome variable that can be explained by the __________________.
predictor
What kind of measurement scale is necessary to be able to meaningfully say that one score is twice as large as another?
ratio
what scale of measurement is: time
ratio
A researcher conducted a single-sample t-test and found t(23) = 2.24. The critical t-value for a two-tailed, one-sample t-test with an alpha level of .05 and 23 degrees of freedom is 2.07. What is the conclusion?
reject the null hypothesis
If the test statistic falls within the critical region, then we can...
reject the null hypothesis
If a teacher gives everyone a grade based on the month they were born, this would be a _____________________ measure of how well students did in the course.
reliable but not valid reliability= repeatability (stating everyone will get an A is reliable) validity= correctness (month of birth is not an accurate measure of someones coursework)
With a very large sample size, you would have a _____________ standard error, which would yield a ______________ confidence interval for the estimate.
small; narrow
A researcher comparing the effect of DBT (Dialectical Behavior Therapy) on male and female depression clients yielded a t-value of t = -1.23. During analysis, the researcher labeled males as group 1 and females as group 2. Which of the following can be concluded?
the effect of DBT was greater for females but the difference was not statistically significant
Which of the following statements cannot be true for a distribution of scores?
the median is above 60% of the scores
If the test statistic we obtain is unlikely (p < alpha) given the null hypothesis, then which of the following statements is TRUE?
the null hypothesis is probably false
The probability of obtaining a test statistic at least as extreme as the one we did given the null hypothesis is known as...
the p-value
To make sure that the sample variance is an unbiased estimator of the population variance, statisticians
use N-1 instead of "N" when calculating variance
Eta squared indicates the percentage of:
variance in a dependent variable accounted for by an explanatory variable.
Under what circumstances is a score that is 2 points above the mean considered an extreme score that is relatively far from the mean?
when the population standard deviation is much smaller than 2
Under what circumstance does the t-distribution look nearly identical to the z-distribution?
when the sample size N is very large
The standard error is _____ (Select all that apply)
+linked to sample size +the standard deviation of the sampling distribution of means +proportional to the standard deviation of the population
What is the effect of decreasing the alpha level (for example, from α = .05 to α = .01)? (Select all that apply)
+decrease the likelihood of rejecting the null hypothesis +increases the likelihood of Type II error
According to the central limit theorem, we can use sampling distributions to estimate population parameters because ______ (Select all that apply)
+the shape of the sampling distribution becomes normal as sample size increases +the mean of the sampling distribution is the same as the mean of the population +the standard deviation of the sampling distribution can be calculated
Which of the following are properties of the chi-square distribution? Select all that apply
- It is skewed positive - Its exact shape depends on the degrees of freedom -It starts at zero
The results of a t-test depends on the sample size. What happens as you increase sample size? Select all that apply
- critical value of t decreases -standard error decreases
Based on the following output from an independent samples t-test, t(21) = 1.34, p >.05, CI = [-5.34, 14.30], what can you conclude? Select all that apply.
- there is not enough evidence that the samples were drawn from populations with different means -fail to reject the null hypothesis
Given an estimated mean value of -13.7 and a standard error of 2 what is the LOWEST value we could estimate for the true mean with 95% confidence? Round to two decimal points.
-17.62
Assume the average height is 66 inches, with standard deviation of 3.5 inches. What is the z-score of a person who is 59 tall? Round your answer to two decimal places.
-2 Z score formula: observed value - mean of the sample / SD z= 59-66 / 3.5 = -2
Given a standard deviation of 4, what is the variance?
16
Which of the following scenarios includes a quasi-independent variable? Sellect all that apply.
-Depression rates are compared between men and women -Younger and older adults are compared in terms of their crystalized intelligence.
Which of the following statements are TRUE regarding hypothesis testing? Select all that apply
-In hypothesis testing, the sampling distribution is used to determine how likely our test statistic is assuming the null hypothesis is true. -As effect size increases, the power to detect an effect increases -As power increases, the probability of incorrectly retaining a null hypothesis decreases.
Which of the following is used to decide whether to reject or retain the null hypothesis? Select all that apply
-P-value -critical value
A study comparing men and women on empathy reported t(22) = 1.92, p>0.05. What can we conclude? Select all that apply
-The results are not statistically significant -The null hypothesis was retained
What does it mean when your observed sample mean falls within the critical region? Select all that apply
-The sample mean is unlikely if the null hypothesis was true -The difference between the predicted and observed value is statistically significant
Given the results r(29) = -.84, p < .05, what are the most appropriate conclusions? Select all that apply
-X and Y have a negative relationship -results are statistically significant
What information is required to calculate 95% confidence intervals around a sample mean?
-estimated population standard deviation -sample size -sample mean
What is the effect of decreasing the alpha level (for example, from α = .05 to α = .01)? Select all that apply
-increases likelihood of type II error -decreases the likelihood of rejecting the null hypothesis
what is considered a weakness of using the mean?
-it is sensitive to extreme values -it can be influenced by outliers
The standard error is _____ Select all that apply
-larger when the population standard deviation is larger -the standard deviation of the sampling distribution of means -smaller when population standard deviation is smaller
If there is a true effect in the population (i.e., if the null is false), what will happen in a statistical test of that effect if you increase the sample size? Select all that apply
-p value becomes smaller -standard error becomes smaller -effect size relatively unchanged
Which of these observed values are more likely to lead to rejecting of the null hypothesis? Select all that apply.
-p-value of 0.007 -A large F-value
The results of a one-sample t-test are reported as follows: t(16) = 1.45, p > .05. What can you conclude? Select all that apply
-sample size was 17 -the null hypothesis was retained
When will the independent samples t-value be more likely significant?
-when the difference between sample means are large -when there is small variability within each group
Assume that you are a participant in a study measuring people's attitudes towards global warming on a scale from 1 ("I am not at all worried about global warming") to 10 ("I am very worried about global warming"). You would like to compare your score to other studies about peoples' reactions to global warming, and the researcher says your standard score is z = -2.4. What can you conclude? Check all that apply.
-you are not really worried about global warming compared to other
On your latest statistics exam, you received a score of 75 and you are told the class average is a 68. If the standard deviation for this exam is 4.5, what can you conclude? Check all that apply.
-your z-score is 1.56 -you did better on this exam than a lot of your classmates
You have a bag of 100 marbles. There are 30 yellow, 15 red, 25 green, 10 blue, and 15 purple marbles, and 5 very special multi-colored marbles. The probability of obtaining the multi-colored marble is _________, which indicates it is a _________ event.
.05; rare
A study reported a correlation between height and weight r = .5, p < 0.05. What is the proportion of variability in people's weight that can be explained by differences in height?
.25 .5 squared
A researcher sampled 27 people who volunteered to pick up trash on the beach. The volunteers filled out a personality survey, and the researcher hypothesized that the volunteers would score higher on the trait agreeableness than the general population. The mean for agreeableness in the general population is considered to be 3, while the sample of volunteers scored a 4.29 (SD = 0.67). Calculate the estimated standard error of the mean. Round your answer to two decimal places.
0.13 SE= SD/ squareroot N SE= .67 / squareroot 27 =.128
An analysis of student records found that 16% of variability in college GPA is explained by students high-school GPA. What is the correlation r between college GPA and high-school GPA?
0.4
Compute sum of squares (SS) for the following sample data: 10, 6, 7, 9, 8 Round to two decimal points
10 SS= 1. find mean: 40/5=8 2.subtract each value from mean (10-8)=2 (6-8)=-2 ... 3.square each value 4. add it up 4+4+1+1+0
A researcher sampled 20 people who volunteered to pick up trash on the beach. The volunteers filled out a personality survey, and the researcher hypothesized that the volunteers would score higher on the trait agreeableness than the general population. The mean for agreeableness in the general population is considered to be 3, while the sample of volunteers scored a 3.21 (SD = 1.94). Calculate the t-statistic for a one sample t-test. Round your answer to two decimal places.
0.48 One sample T-test: (sample mean - pop mean) / SD/ squareroot of N t= (3.21-3) / 1.94 / squareroot 20
Your closet contains a stack of shirts. 9 of those shirts are tank tops, 5 are button-up shirts, and 7 are regular T-shirts. What is the probability of choosing anything OTHER THAN a tank top? Give you answer as a proportion (not percent).
0.57
The average weight of newborn infants is 7.4 pounds, with standard deviation of 1.1 pounds. What is the z-score of a baby who was 8.3 pounds at birth? Round your answer to two decimal places.
0.82 Z= x-u/o z=(observed value)(mean of sample)/ (SD)
A researcher investigated the relationship between personality type and risky behavior. She gave personality inventories to 100 high school students and asked each one if he or she had ever driven drunk. She found that out of 60 extroverts, 45 had driven drunk. Out of 40 introverts, only 10 had driven drunk. What is the degrees of freedom for this test?
1
Given a variance of 117, what is the standard deviation? Round to two decimal points.
10.82
The mean score on a novel questionnaire of empathy is 12, with a standard deviation of 4.2. What is the standard error of the mean for a sample size of 12? Round your answer to two decimal places.
1.21 SE= SD / square root of N SE= 4.2 / squareroot 12
A typical U.S. adult gets 6.8 hours of sleep per night. A sleep researcher tested if college students sleep less than the general population. He asked 24 college students how much sleep they got the night before (in hours) and found that on average they slept 6.3 hours. The researcher is running a one-sample, one-tailed t-test to test his hypothesis. How many degrees of freedom are there for this test?
23
A study comparing Oregonians and Californians on their tolerance to wine drinking reported t(21)=1.75, p > 0.05. What was the sample size?
23 independent samples t test: df= n-2
An administrator is tasked with picking an operating system (OS) for the new computers. He surveys the office to find out which OS the other employees prefer- Mac or Windows. Out of 100 employees, he finds that 75% prefer Mac, while the rest prefer Windows. Calculate χ2to compare the proportion of employees who prefer Mac to Windows. For each step in your calculations, round your answers to the nearest hundredth before entering into the next step. Round your final answer to the nearest hundredth.
25
A researcher reports these results from an independent samples t-test, t(89) = 3.80, p = .044, CI95 = [3.05, 12.67], d = .65. What is the value of the test statistic?
3.80
A researcher was convinced that his research hypothesis was true and extra-sensory perception (ESP) is real. He was determined to repeat his ESP study until he finds it. He ran a total of 80 experiments. His colleague, who does not believe in ESP, pointed out that with his alpha set to alpha = 0.05, he is bound to likely "find" ESP in at least one of his 80 experiments. In how many experiments, out of the 80, would he be expected to reject the null hypothesis, even if it was true?
4 HOW SOLVE?
If the mean IQ is 100 with SD = 15, what is the approximate probability that a randomly chosen sample of 9 people will have a mean IQ more extreme than 110? Remember that extreme can refer to both extremely large and extremely small sample means.
4% HOW TO SOLVE
A t-distribution with which of the following degrees of freedom most closely resembles the standard normal distribution?
40
The results of a one-sample t-test are reported as t(42)=2.56, p < 0.05. What was the sample size?
43
The researcher runs a one-sample, two-tailed t-test (α=.05) and reports the following results: t(58) = 2.78, p = .023, CI95= [35.4, 39.5]. How many people were sampled?
59
A 3 X 2 factorial design will have ______ different cell means.
6
Compute variance (MS) for the following sample data: 9, 6, 5, 4, 2 Hint: Make sure to use n-1. Round to two decimal points
6.7 MS= SS/ DF 1. find SS 2. divide by df
In an experiment, you give 61 people a personality inventory, and find that your sample has a mean extraversion score of 6.7 with a standard deviation of 1.9. What is the upper limit of the 95% confidence interval around the mean? Round your answer to two decimal places.
7.18 1) SE= SD/square root of N SE=1.9/ squareroot 61=.24 for 95% M+/- 2*SE 2) .24 x 2=.48 3) 6.7 + .48= 7.18
In an experiment, you give 17 people a personality inventory, and find that this sample has an average score of 65 for extraversion with a standard deviation of 11.4. What is the upper limit of the 95% confidence interval of the mean?
70.42
The quantitative GRE (Graduate Record Examination) has a mean of 150 and standard deviation of 9. What is the approximate percentile rank for a student who scored 155?
70th (draw out distribution counting by SD of 9 then look at percentile 155 falls in)
You are curious about your score on a psychology exam, and your teacher tells you that your z-score is 1.6. The class average is 70 out of a possible 100 points, with a standard deviation of 3.36. What is your score on the exam?
75
A team of researchers hypothesized that men and women use different strategies to maintain happiness. They surveyed men and women and asked which of the following three strategies they used to maintain happiness (participants had to choose only one): friends, exercise, or academic accomplishments. Among the men, 72 indicated friends, 84 indicated exercise, and 40 indicated academic accomplishments. Among the women, 70 indicated friends, 90 indicated exercise, and 71 indicated academic accomplishments. Calculate the expected frequency for women who use friends to maintain happiness. For each step in your calculations, round your answers to the nearest hundredth before entering into the next step. Round your final answer to the nearest hundredth.
76.82
Given: The total number of participants = 86 Number of groups = 6 SSb = 9 SSw = 165 What is the degrees of freedom within?
80 dfw= # of participants - # of groups 86-6=80
Given a normal distribution, what is the area under the curve between -1 and +2 standard deviations from the mean? Given your answer in percent (%)
81.86 or 82 (with margin 2)
Compute the variance of the following sample dataset: 9, 2, 7, 2, 9, 9, 9, 8, 7, 11 (Hint: Be sure to use N-1 and round to two decimal points)
9.12
A researcher finds that the standard error of the mean is 9.85 for a sample size of 86. What is the population standard deviation?
91.35
Researchers believe there may be a link between breast feeding and autism. They conducted an online survey and found that out of 100 people who reported being breast fed, 6 were diagnosed with autism. Of the 80 people who reported using a formula as infants, 8 were diagnosed with autism. Calculate the expected frequency for people who were breast fed and have not been diagnosed with autism. For each step in your calculations, round your answers to the nearest hundredth before entering into the next step. Round your final answer to the nearest hundredth. You Answered
92.22
For which of the following would a paired t-test be appropriate? Select all that apply.
A)A researcher is looking at the relationship between agreeableness and extraversion on the same individuals B)A researcher is studying neuroticism in parent-child dyads. C)A researcher is studying differences in personality traits between left-handed and right-handed people. D)A researcher is comparing performance before and after a training program. ANSWERS: B, D
Which of the following questions would be most likely be tested using a paired samples t-test?
A)Is there a difference in the verbal ability between US and Canadian students? B) Effect of cognitive-behavioral therapy on depression C)Are obesity rates different in California and Illinois? D)Is the average birth weight of babies born in Alaska similar to that in the US in general? ANSWER: B
Which of the following is an example of a statistical hypothesis?
A)Older adults have a higher proportion of false alarms on a recognition test than younger adults. B)People are more likely to generate false memories with age. C)Aging impacts memory function. D)Recognition and recollection are distinct functions of memory. ANSWER: A
In which of these scenarios would a researcher use an independent samples t-test?
A) A cognitive psychologist compares the mean IQ score of a sample of UO students to the mean IQ score of the general population. B) A personality psychologist tests for sex differences in consciousness scores in young adulthood. C) A cognitive psychologist compares average words remembered from a word-list between three different age groups. D)A clinician tests the effectiveness of a new psychotherapy by comparing levels of depressive symptoms before and after the treatment. ANSWER: B
Researchers wanted to compare the level of happiness in US and Finland. Which of the following statistical tests would be appropriate for this analysis?
A) one sample t B)independent samples t C) paired t ANSWER: B
In which of these scenarios would a researcher use a one-sample t-test?
A)A personality psychologist compares whether levels of consciousness in a random sample of college students at her college differ from the known mean of a typical student. B)A clinician tests the effectiveness of a new psychotherapy by comparing levels of depressive symptoms before and after the treatment. c)A cognitive psychologist studying autobiographical memories compares the amount of unique details in memories between children (6-10), young adults (18-22), and older adults (50+). D)A social psychologist tests for gender differences in implicit racial bias. ANSWER: A
Which scenario would best be analyzed using a repeated-measures ANOVA?
A)Shannon tests her smoking cessation program on a group of people and measures the smoking behavior of the same people before, during, and after treatment. B)Carrie hands out questionnaires to determine the association between perceived stigma and help-seeking behaviors of people living with HIV. C)Onur wants to compare the body esteem of males compared to females. D)Jean conducts an experiment on how the severity of stress impacts memory during an exam. ANSWER: A
Which of the following statements regarding hypothesis testing is TRUE?
A)With proper design, we can eliminate error completely B)We want significance level alpha to be as high as possible, such as .95 or .99 C)We can only minimize error, not eliminate it. ANSWER: C
A psychologist is interested in whether or not handedness is related to gender. Specifically she wants to know if the percentage left-handed men in the population is different from the percentage of left-handed women. She collected data on handedness for 200 men and 200 women. What type of statistical test would be appropriate?
Chi-square test of independence
A psychologist is interested in comparing the demographics of grand jury members to demographics of the population to see if grand jury panels are really representative of the population. The first variable she examines is age. The percentage of people over 65 in the population is 25%, but out of 200 people empaneled for grand jury trials, 76 (38%) were aged 65 or more. She wants to know if the proportion of people over 65 on grand juries is significantly different than that proportion in the population. What test should she use?
Chi-square goodness of fit test
A researcher reports that people need eight hours of sleep to function efficiently during the day. In her review she states that 70% of the American population gets less than eight hours of sleep a night, 20% gets eight hours, and 10% gets more than eight hours. You survey 100 college students and find 80% get less than eight hours of sleep a night, 15% get eight hours, and 5% get more than eight hours. How do college students' sleep patterns compare to the general public? Which of the following is the appropriate null hypothesis?
H0: P = (.7, .2, .1)
With a very small sample size, you would have a _____________ standard error, which would yield a ______________ confidence interval for the estimate.
Large; wide
You are analyzing a data set with multiple continuous predictors and one continuous outcome variable. Which statistical test should you use?
Multiple regression
A researcher believes that recall of verbal material differs with the level of processing. He divided his subjects into three groups. In the low processing group, participants read each word and were instructed to count the number of letters in the word. In the medium processing group, participants were asked to read each word and think of a word that rhymed. In the high processing group, participants were asked to read each word and think about something that happened to them that would relate to that word. Each group was allowed to read the list of 30 words three times, then they were asked to recall as many of the words on the list as possible. If the researcher wants to know whether the three groups have different amounts of recall, what type of statistical test should be used?
One-way between-subjects ANOVA
A researcher investigated the relationship between personality type and risky behavior. She gave personality inventories to 100 high school students and asked each one if he or she had ever driven drunk. She found that out of 60 extroverts, 45 had driven drunk. Out of 40 introverts, only 10 had driven drunk. Which of the following is the appropriate null hypothesis?
P(extrovert and has driven drunk) = P(introvert and has driven drunk) P(extrovert and has not driven drunk) = P(introvert and has not driven drunk)
A researcher investigated the relationship between personality type and risky behavior. She gave personality inventories to 100 high school students and asked each one if he or she had ever driven drunk. She found that out of 60 extroverts, 45 had driven drunk. Out of 40 introverts, only 10 had driven drunk. Which of the following is the appropriate alternative hypothesis?
P(extrovert and has driven drunk) ≠ P(introvert and has driven drunk) P(extrovert and has not driven drunk) ≠ P(introvert and has not driven drunk)
A statistically significant sex difference in spatial ability was found between males (n = 2500) and females (n = 2600) in South Africa. A Cohen's d value was obtained yielding a value of d = 0.13. What can we say about these results in the purview of this information?
This is a small effect, so the significant difference should be interpreted cautiously
A researcher reports the following results from a paired samples t-test (two-tailed, alpha = .05): t(310)= 1.01, p = .156 Which of the following could be the 95% confidence interval for the mean difference score?
[-3.12, 2.66] HOW TO SOLVE
In repeated measures ANOVA, removing variability due to individual differences reduces the error term in the denominator of the F-ratio. This results in....
a more powerful test
In a two-tailed test with α=.05, each tail should span _____% of the sampling distribution.
accepted answers? 0 0.025 2.5
Marlieke measured extraversion on a six-point scale in a sample of Dutch college students. She found the mean to be 3.53. Can we conclude at alpha = 0.05 that Dutch students are less extraverted than Americans? American population parameters for extraversion are µ = 3.84, σ = 1.18.
answer depends on sample size
When you run an ANOVA with more than two-groups and end up with a significant result, what can you conclude?
at least one population mean is different from at least one other population mean
One way to think about the F-value in ANOVA is as a ratio comparing variability due to treatment and variability due to error. The variability due to treatment in this calculation refers to the...
between group variance
For a particular variable, Sarah adds up all the values, then divides by the total number of values. This results in a measure of ___________________ called the _____________.
central tendency; mean
You are interested in learning if people drink because they think it will increase their sociability levels. To investigate this, you survey 150 people and get the following results: 75 people drink and think they are sociable, 20 people drink and don't think they are sociable, 30 people do not drink and think they are sociable, and 25 people do not drink and do not think they are sociable. Which statistical test you would use to answer the research question and/or analyze the data described?
chi-square test of independence
The most commonly used measure of effect size for an independent samples t-test is
cohens D
The MS within is sometimes referred to as the error variance. A key source of error variance is ...
individual differences
In a one-way, repeated-measures ANOVA, which equation is used to calculate dfResidual?
dfSubjects × dfTreatment
In a one-way, repeated-measures ANOVA, the degrees of freedom associated with variability due to the independent variable are called _____.
dftreatment
The null hypothesis for an independent samples t-test states that the difference between the population means is
exactly zero
We can only run a chi-square test if the ____________ is at least 5.
expected frequency in each cel
A study design with more than one grouping variable is called....
factorial design
Which of the following would violate the independence assumption for a one-sample t-test?
if the same person participated in the study multiple times
A researcher wants to compare males and females on smoking behavior. Smoking is measured as the number of cigarettes smoked each day. Which statistical test you would use to answer the research question and/or analyze the data described?
independent samples t test
You are interested in sex differences in attitudes toward homosexuality. Specifically, you want to test the idea that women are more accepting of homosexuality and thus have more positive attitudes toward homosexuality than do men. You collect data from 10 heterosexual men and 10 heterosexual women using a scale that measures homophobia (note: larger scores equal more positive attitudes). The collected data look like this:
independent samples t test
A researcher is testing the effects of stress on people's moods. The experimental condition has 25 participants. The control condition has 31 participants. Which statistical test you would use to answer the research question and/or analyze the data described?
independent samples t-test
What statistical test should be used to compare psychology knowledge of students who are psychology majors with those who are not?
independent-samples t-test
what scale of measurement is: Temperature (in degrees Fahrenheit)
interval
Which situation will lead to the largest F-statistic?
large differences among group means and small within-group variability
For interval and ratio scale data, which measure(s) of central tendency is/are appropriate? Check all that apply.
mode, mean, median
A psychologist wants to investigate the relationship between stress and mental health during the first year of college. The researcher developed scales that measure 1) the frequency of stressful events, 2) the perceived importance of these events, 3) the desirability of such events, and 4) the impact of these events of the student. The researcher had 150 first year college students fill out this questionnaire as well as a Symptom Checklist, which is designed to assess the presence or absence of psychological disorders. What statistical procedure would help this researcher discover if psychological disorders can be predicted from the different aspects of stress that have been measured?
multiple regression
An eta squared value of 0 indicates ________
no effect of group
what scale of measurement is : type of pet (dog, cat, fish)
nominal
By following two groups of people, one group who smokes (and smoked before entering the research study), and one group who doesn't smoke (and never smoked before entering the research study) a researcher is engaging in _________________ research. Check all that apply.
non-experimental quasi-experimental
Principal Jones collects data on how students in her school performed on a standardized test that is measured on an interval scale. She wants to compare her school's performance to the mean of the rest of the schools in the state. She does not know the standard deviation of scores on this test for the state. Which statistical test you would use to answer the research question and/or analyze the data described?
one sample t test
Survey data suggest that college students spend an average of 30 hours per week studying, with a standard deviation of 4 hours. You wonder if student athletes study the same amount. You survey 25 athletes and find that they study 25 hours per week. Which statistical test you would use to answer the research question and/or analyze the data described?
one sample z test
Researchers want to know if people in Oregon spend more time outdoors than people in the US in general. They collect a sample of Oregonians and ask them how many hours per week they typically spend outdoors. Which of the following statistical tests would be appropriate for this analysis?
one samples t test
A political analyst is interested in how urban, suburban, and rural voters differ in exposure to political campaign ads. They measure the number of minutes per week spend watching public television. What test would they employ?
one-way between subjects ANOVA
A researcher wants to know if class (freshman, sophomore, junior, senior) is associated with number of parties a student attends each term. Which statistical test you would use to answer the research question and/or analyze the data described?
one-way between subjects ANOVA
Academic Support Services was interested in doing a study to determine if the location where a student studies for exams affects his or her test performance. All subjects were randomly assigned to one of three conditions: study in your dorm room, study in the student union, or study in the actual classroom where the test will be administered. The students' test scores were compared. Which statistical test you would use to answer the research question and/or analyze the data described?
one-way between subjects ANOVA
In a clinical trial, a third of participants are assigned into the psychotherapy treatment group, one third into the psychotherapy + medication group and one third into a control (no treatment) group. Which test should be used to compare the degree of depressive symptoms between groups at the conclusion of the trial?
one-way between subjects ANOVA
When do we conduct post-hoc tests?
only after ANOVA results are significant
A researcher is interested in the age at which infants learn to recognize faces. He decides to measure infant age as "number of days since birth". This represents the researcher's ____________________ definition
operational
Chime wanted to know if students' sleeping habits vary over the semester. She surveyed 100 students and asked them to keep track of how many hours of sleep they got per night during the first two weeks of school, the two weeks before break, the two weeks after break, and during the last two weeks of school. Which statistical test you would use to answer the research question and/or analyze the data described?
repeated measures ANOVA
Stress decreases quality of sleep. This is an example of a __________ hypothesis.
research
Type II error is when we...
retain the null hypothesis when it is actually false.
Which of the following is the best description of a Type II error?
retaining a false null hypothesis
If the Pearson correlation coefficient is r = .9, then the slope in the regression equation will be
small or large, depending on the measurement units of the variable.
What is the difference between a χ 2 test of independence and a χ 2 goodness-of-fit test?
the test of independence examines the relationship between two variables, while the goodness-of-fit test examines just one variable
Unlike one-sample z-test, one-sample t-test can be used even when we do not know __________
the value of the population standard deviation
Which of the following is true about the null and alternative hypothesis?
they make opposite predictions
