PSYC 210 LC
The value of an observation is 13; the value of the mean is 18. The value of the deviation is _____.
-5
In a standard normal curve, the standard deviation is:
1.00
A shopper at a local supermarket spent the following amounts in Jacob's last eight trips to the store: $32.92, $14.14, $30.80, $27.34, $28.34, $75.58, $27.41, and $22.94. The value of the mean is $_____. (Give answer as XX.XX.)
32.42
Which distribution has a greater spread?
Confidence interval
Which statement is true?
The mean and median do not measure center in the same way.
A confidence interval is:
an interval estimate that would include the population mean a certain percentage of the time if one had repeatedly sampled from the same population.
When creating a frequency polygon, subtract the interval size from the bottom midpoint and add the interval size to the top midpoint. By adding these two new values to the frequency polygon, one is:
grounding the shape.
If the symbol < is found in the _____, one will declare the test to be one-sided.
null hypothesis
The _____ is the collection of all items or individuals of interest in a study.
population
To determine the critical values for an independent-samples t test, use the _____ the degrees of freedom for each sample.
sum of
When conducting hypothesis testing with correlation, the null hypothesis is:
ρ = 0
A shopper at a local supermarket spent the following amounts in Jane's last eight trips to the store: $32.92 $14.14 $30.80 $28.34 $75.58 $36.33 $33.51 $22.94. The amount of _____ spent is an outlier.
$75.58
Suri has just taken a statistics exam, and she wants to calculate a confidence interval to represent the scores in her class. The test mean was 75 with a standard deviation of 5. There are 30 students in the class. The 99 percent confidence interval for the class is:
(72.65, 77.35).
Corinne has just taken a statistics exam, and she wants to calculate a confidence interval to represent the scores in her class. The test mean was 75, with a standard deviation of 5. There are 30 students in the class. The 95 percent confidence interval for the class is:
(73.21, 76.79).
Consider a study testing the hypothesis that, on average, individuals who take a new cognitive enhancement drug will remember more words in a recall memory test than those in the population who do not take the drug. Given this information, the 95 percent confidence interval is:
(8.25, 11.75).
LaTanya has just taken a statistics exam, and she wants to calculate a 90 percent confidence interval to represent the scores in her class. What are the z statistics that fall at each line marking the middle 90 percent of scores in the distribution?
+/−1.64
Which of these coefficients indicates a weak correlation?
-0.04
Consider a study testing the hypothesis that, on average, individuals who take a new cognitive enhancement drug will remember more words in a recall memory test than those in the population. Given this information, the Cohen's d value is:
-0.50.
A research study has an M = 4.12, μM = 5.63, and an sM = 1.65. What is the t statistic? (Answer using 2 decimal places.)
-0.92
What is the effect size for a paired-samples t test in which the mean of 15 difference scores is -11.2 and the estimated population standard deviation is 7.28?
-1.54
A consumer advocate is interested in evaluating the claim that a new granola cereal contains "4 ounces of cashews in every bag." The advocate recognizes that the amount of cashews will vary slightly from bag to bag, but she suspects that the mean amount of cashews per bag is less than 4 ounces. To check the claim, the advocate purchases a random sample of 40 bags of cereal and calculates a sample mean of 3.68 ounces of cashews. Assuming that the standard deviation is 0.8 ounces, what is the value of the test statistic for testing H0: μ = 4?
-2.53
If a researcher rejects the null hypothesis based on the results of a paired-samples t test, to draw the same conclusion based on the confidence interval:
0 would not fall within the bounds of the confidence interval.
Based on the graph, determine the p level that was used in the t distribution. The df for the test was 4.
0.05
If an outcome is said to be rare, the probability of the outcome might be:
0.1
Consider a study testing the hypothesis that, on average, individuals who take a new drug will remember more words in a recall memory test than those given a placebo. The scores, numbers of words remembered, are provided for individuals in each group. Drug Group: 7, 9, 8, 9, and 8 Placebo Group: 5, 7, 6, 8, 9, and 7 The variance version of standard error for the Placebo Group needed to complete the final calculation of the independent-samples t test is _____. (Answer using 2 decimal places.)
0.24
At benefit parties, many charities give a door prize to one guest chosen at random. At one party there are 200 men and 180 women present. What is the probability the prize goes to a woman?
0.474
In an effort to improve a statistics course, Professor Delilah wants to interview 30 randomly chosen students about their attitudes toward the class. If there are 800 students currently enrolled, how would she number them to select a random sample using the table of random digits?
001, 002, 003, ..., 799, 800
The weights of adult female California sea lions are approximately normal with mean µ = 220 pounds and standard deviation s = 8 pounds. The standard deviation of the sampling distribution of M created from random samples of size 36 is _____. (Answer using 2 decimal places.)
1.33
The weights of adult female California sea lions are approximately normal with mean µ = 220 pounds and standard deviation s = 8 pounds. What is the standard deviation of the sampling distribution of M created from random samples of size 36?
1.33
When computing a 90 percent confidence interval, one will use z = ±_____. (Answer using 2 decimal places.)
1.64
When computing a 95 percent confidence interval, one will use z = ± ______. (Answer using 2 decimal places.)
1.96
Dr. Harrison has a sample of scores from four different populations. Which sample MOST closely follows a normal distribution?
10, 11, 15, 15, 15, 15, 18, 19
The distribution of comprehensive scores of all the students taking an intelligence test in 2010 is approximately normal with mean µ = 100 and standard deviation s = 15. What is the mean of the sampling distribution of M created from random samples of size 16?
100
Thomas conducts a study comparing the performance of biology majors and psychology majors who have taken the same introductory psychology quiz. The scores, out of 100, are provided for individuals in each group. Biology majors: 87, 78, 77, 85, 83, 88, and 73 Psychology majors: 87, 96, 92, 90, 90, and 91 The total degrees of freedom, dftotal, needed to determine the characteristics of the comparison distribution, which is necessary to complete the final calculation of the independent-samples t test, is _____.
11
Consider a study testing the hypothesis that, on average, individuals who take a new cognitive enhancement drug will remember more words in a recall memory test than those in the population who do not take the drug. Given this information, the upper bound of the 90 percent confidence interval is _____. (Answer using 2 decimal places.)
11.47
Consider a study testing the hypothesis that, on average, individuals who take a new cognitive enhancement drug will remember more words in a recall memory test than those in the population who do not take the drug. Given this information, the upper bound of the 95 percent confidence interval is _____. (Answer using 2 decimal places.)
11.74
Terrance is creating a grouped frequency table and wants to determine the appropriate size for his intervals. His data set has a range of 60, and he would like to have 5 different intervals. The appropriate interval size for Terrance's data is ______.
12
The tallest person ever confirmed by Guinness World Records was Robert Ludlow of the United States, who was 8 feet, 11.1 inches tall. Heights of American men are approximately normal with a mean of 69.3 inches and a standard deviation of 2.8 inches. Ludlow's z score is _____. (Answer using 2 decimal places.)
13.5
Use the standard normal table (use the table reader, the table in the textbook, or a graphing calculator) to complete the statement: _____ percent of the total area under the curve is to the right of z = 0.87. (Answer using 2 decimal places.)
19.22
Jared has a sample of scores from four different populations. Which sample MOST closely follows a normal distribution?
2, 4, 5, 5, 6, 6, 6, 7, 7, 9
Suppose one calculates a 95 percent confidence interval for μ based on a random sample of 25 individuals. The critical value for this confidence interval is t = ±_____. (Answer using 3 decimal places.)
2.064
When computing the variance using a sample of size N = 22, one should divide the sum of squared deviations by _____. (Give answer as XX.)
22
The probability of being dealt two of a kind in five-card stud poker is 2.6 percent. This means that, on average, there will be _____ times that someone gets two of a kind dealt to them in every 1,000 hands dealt.
26
A shopper at a local supermarket spent the following amounts in Sam's last seven trips to the store: $32.92, $27.34, $26.34, $36.33, $33.51, $27.40, and $22.94. The value of the median is $_____. (Give answer as XX.XX.)
27.40
A shopper at a local supermarket spent the following amounts in Peter's last seven trips to the store: $14.14, $30.80, $27.34, $28.34, $75.58, $27.42, and $22.94. The value of the median is $_____. (Give answer as XX.XX.)
27.42
A shopper at a local supermarket spent the following amounts in Emma's last seven trips to the store: $30.80, $27.34, $28.34, $75.58, $33.51, $27.41, and $22.94. The value of the median is $_____. (Give answer as XX.XX.)
28.34
Suppose that the population of drivable cars get an average of 25 miles per gallon (mpg), with a standard deviation of 5 mpg. In order to qualify as "efficient" and receive a new tax credit, a car must be at the 85.08 percentile or higher. How many mpg would qualify a car as "efficient"?
30.20
Josephine has a verbal SAT score of 450. The SAT score has a mean of 500 and a standard deviation of 100. Josephine's percentile rank is _____. (Answer using 2 decimal places.)
30.85
A shopper at a local supermarket spent the following amounts in Ben's last eight trips to the store: $32.92, $14.14, $30.80, $27.34, $28.34, $75.58, $36.33, and $33.51. The value of the mean is $_____. (Give answer as XX.XX.)
34.87
Consider a study testing the hypothesis that, on average, individuals will remember more words in a recall memory test when they are given a new cognitive enhancement drug than when they are given a placebo. The scores, numbers of words remembered, are provided for five individuals tested in both conditions. Drug condition: 7, 9, 8, 9, and 8 Placebo condition: 5, 7, 6, 8, and 9 The degrees of freedom needed to assess the results of the paired-samples t test is _____.
4
The world's biggest dog weighs in at a massive 282 pounds, or 4,512 ounces, while the world's smallest dog weighs in at just 18 ounces. What is the range of scores for the weights of the dogs in ounces?
4,494 ounces
Alex, a researcher in the psychology department, is creating a grouped frequency table for one of his data sets. The highest value in his data set is 58.7 and the lowest value is 19.3. What is the range of values for Alex's data set?
40
Consider this small population of scores: 345, 465, 567, 890, 678, 798, 567, 789, 678, and 456. The mean is 623.30, and the standard deviation is 164.90. Given a z score of -1.01, the original raw score is _____. (Answer using 2 decimal places.)
456.75
For random samples of size 16 from a population with mean µ = 48, the mean of the sampling distribution of M is _____. (Answer using 2 decimal places.)
48
With p = 0.05, how often will the null hypothesis be rejected?
5 percent of the time
Angel conducts a study to compare the performance of two classes of students on a quiz taken during the first term of their freshman year. The scores, out of 100, are provided for nine students in both classes. Class 1: 87, 78, 87, 85, 93, 98, 83, 82, and 73 Class 2: 87, 86, 92, 90, 90, 91, 89, 78, and 76 The standard deviation of the comparison distribution, s, needed to complete the final calculation of the paired-samples t test is _____. (Answer using 2 decimal places.)
5.18
Consider a study testing the hypothesis that, on average, individuals who take a new cognitive enhancement drug will remember more words in a recall memory test than those in the population who do not take the drug. Given this information, the lower bound of the 99 percent confidence interval is _____. (Answer using 2 decimal places.)
8.37
A distribution has mean 65 minutes and standard deviation 10 minutes. If the instructor wants to set a time limit so that at least 95 percent of students are able to finish a test, _____ minutes should be allowed. (Answer using 2 decimal places.)
81.50
The distribution of bladder volume in men is approximately normal with a mean of 550 milliliters and a standard deviation of 100 milliliters. What proportion of men has a bladder volume larger than 450 milliliters?
84 percent
Elise has a sample of scores from four different populations. Which sample MOST closely follows a normal distribution?
95, 98, 99, 99, 100, 100, 100, 101, 102, 104
Suppose one is testing H0: μ ≥ 100 versus H1: μ < 100. Which of these will have the smallest p value?
=70
Consider a study testing the hypothesis that, on average, individuals who take a new cognitive enhancement drug will remember more words in a recall memory test than those in the population who do not take the drug. Given this information, the lower bound of the 95 percent confidence interval is _____. (Answer using 2 decimal places.)
8.25
Suppose someone is testing H0: μ = 50 versus H1: μ ≠ 50. Which of these will have the smallest p value?
=56
Order the data sets from the smallest to the largest in terms of standard deviation.
Data set A, Data set C, and Data set B
Which symbol represents sample size?
N
All of these variables can be continuous observations EXCEPT:
Olympic medal status: gold, silver, or bronze.
Which scatterplot would give the larger value for r?
Plot B
Which of these is the MOST likely cause of an individual's persistent belief in the predictive power of horoscopes?
confirmation bias
In a study examining whether gender predicts political views, male and female are:
levels of the independent variable.
The formula N/2 + 0.5 is used to calculate the:
ordinal position of the median.
The null hypothesis is _____ when the test statistic falls beyond the cutoffs.
rejected
Establishing validity is usually much more difficult than establishing _____.
reliability
Which distribution has a greater spread?
t
Dr. Werner is interested in the political attitudes of male college students. He sends an e-mail message to all men enrolled at the three local community colleges in which he asks for volunteers to participate in a study. He receives replies from 138 men who sign up to participate. On the day of the study, 78 men show up and complete the study. In this example, the sample is:
the 78 men who show up and complete the study.
Which statement about Type II errors is true?
A Type II error typically results in failure to take action—for instance, a research intervention is not performed or a diagnosis is not given.
Which statement is false?
A measure can have poor reliability and high validity.
What would a researcher use in a study to report the size of the difference between means when he is examining the academic performance of men and women?
Cohen's d
Josh and Emma are taking the same course from different professors. Josh gets a final score of 437 on a 500-point scale, the class mean is 407, and the standard deviation is 9. Emma gets a final score of 887 on a 1000-point scale, the class mean is 857, and the standard deviation is 18. Which statement is true?
Given their z scores, Josh did better with respect to his class than Emma did with respect to her class.
Dr. Philips conducts a study showing that the correlation between grade point average (GPA) and number of hours of studying per week is 0.47. Based on this information, which statement is true?
Individuals who have low GPAs tend to study less per week than individuals who have high GPAs.
In which situation should one NOT use a parametric hypothesis test?
It is clear that the dependent variable is nominal or ordinal.
Which statement is true of the normal curve?
Most of the scores are clustered in the middle.
While watching TV with a friend, Shawn sees a commercial for a diet plan in which there are several before and after images of individuals who have lost considerable weight on the plan. If Shawn's friend thought the ad presented strong evidence that the plan would work, what should Shawn tell his friend?
No, the data came from a volunteer sample, so it is very unlikely to be generalizable.
Which statement is true?
Ordinal variables have rankings as values.
Choose the correct formula for computing the mean value of a sample of eight participants with the following scores: 12, 11, 25, 21, 20, 19, 17, and 16.
SX/N
Dr. Dover reads an article on a study designed to examine the efficacy of a new intervention to increase self-esteem in teenage girls. In the article, among other important information, the authors reported 95 percent statistical power. Which statement is false?
The authors had a 95 percent chance of making a Type I error.
Consider this confidence interval interpretation: Simon is confident that the true mean weight of all black bears is between 344.8 and 361.2 pounds. What needs to be done to fix this statement?
The confidence level is either not reported or wrongly reported.
Using the t distribution below, determine whether the null hypothesis will be rejected if the t statistic is -1.115.
The null hypothesis will fail to be rejected.
How does an increase in the sample size affect the sample mean?
The sample mean gets closer and closer to μ.
Dr. Warren designed a new test to assess depression in high school students and determines that it has a coefficient alpha of 0.27. Based on this information, which statement is true?
The test does not have sufficient internal consistency to be used as a diagnostic tool.
The histogram below gives the distribution of the percentage of a sample of British males who smoked for 25 years. Why is this particular display not a good choice? Select the BEST reason.
There are too many classes, making it difficult to determine the shape of the distribution.
In the formula for standard error, why is s used instead of σ?
This change is due to the sample standard deviation being used instead of the population standard deviation.
When figuring out financial aid packages, financial aid offices are interested in studying how much a student might reasonably be able to earn. A simple random sample of students at one university in southern Georgia was interviewed about how much money they earn each month. The resulting 95 percent confidence interval was ($150.75, $223.74) for those with part-time jobs. What should this confidence interval contain?
This confidence interval should contain the true mean monthly earnings for all students with part-time jobs at that university.
If researchers reject the null hypothesis when it is actually correct, they have made a _____ error.
Type I
Which statement is false?
When calculating a confidence interval using a z distribution, the population mean is used in the calculations.
Bell conducts a study comparing the performance of biology majors and psychology majors who have taken the same introductory psychology quiz. The scores, out of 100, are provided for individuals in each group. Biology majors: 87, 78, 77, 85, 83, 88, and 73 Psychology majors: 87, 96, 92, 90, 90, and 91 Given a two-tailed test and a p level of 0.05, the 95 percent confidence interval is:
[-15.10, -3.76].
Which of these is the BEST way to present the pattern of responses for a specific variable?
a frequency table
In which type of distribution does the tail extend to the left?
a negatively skewed distribution
What type of distribution is bell-shaped, symmetrical, and has only one mode?
a normal distribution
Which type of distribution is central to many calculations in statistics?
a normal distribution
In a test of significance, one will make a claim and ask if the data gives evidence _____ it.
against
A population distribution has a normal shape with mean µ = 50 and standard deviation s = 4. Consider two sampling distributions from this population distribution. Sampling distribution #1 is created from the sample means of all possible random samples of size N = 8; sampling distribution #2 is created from the sample means of all possible random samples of size 64. The shape of sampling distribution #1 is _____ the shape of sampling distribution #2.
approximately normal, just like
In the first step of hypothesis testing, the populations, comparison distributions, and _____ must be identified.
assumptions
Dr. Evans conducted an experiment that included thousands of participants and revealed a statistically significant result. Because it is not surprising that studies with large sample sizes produce statistically significant results, Dr. Evans should _____ to reflect the importance of her findings in a way that is not affected by sample size.
calculate a measure of effect size
The confidence interval is:
centered around the mean of the sample.
Dr. Lawrence designed a new test to assess depression in high school students. Before using the test in his research, which of these should be demonstrated?
coefficient alpha greater than 0.90
Dr. Simon conducts a study to test whether a new drug developed to treat general anxiety disorder works better than the usual treatment of cognitive behavioral therapy (CBT). Twenty male and 20 female participants are randomly assigned to get either the drug or CBT. After 4 weeks of treatment, all of the participants complete the General Anxiety Test (GAT), which allows them to be classified as severely depressed, moderately depressed, or mildly depressed. In this study, drug therapy and CBT can be referred to as values or _____ of the independent variable.
conditions/levels
A(n) _____ is an interval estimate that would include the population mean a certain percentage of the time if one had repeatedly sampled from the same population.
confidence interval
A college student does well on his first two statistics tests, which he took using his blue mechanical pencil. For all future statistics tests, he decides to use only his blue mechanical pencil. Although he does not do well on the next two tests, after the fifth test and a superb score. He remarks to his friend, "See, I told you the pencil gets me high scores! I should start using it for all of my tests." In this scenario, the student's focus on the three good scores and his dismissal of the two bad scores demonstrates:
confirmation bias.
The length of a randomly selected person's foot is an example of a _____ variable.
continuous
If a researcher conducts a study to determine whether gender predicts political party affiliation, political party affiliation is a(n) _____ variable.
dependent
A measure of how far an observation is from the mean is a(n) _____ score.
deviation
In order to determine the critical values when conducting a paired-samples t test, one needs to know:
df.
If the null hypothesis is rejected, the researcher has observed a t statistic that _____ the population.
differs from
The sign of the correlation coefficient indicates the _____ of the positive or negative correlation.
direction
One way to create a random sample of students in a class is to:
draw names out of a hat.
Less overlap between two population distributions indicates a larger _____.
effect size
Two studies were conducted to compare the academic performance of men and women, using two different tests. One study reports d = 0.23, and the other reports d = 0.52. Based on this information, these two studies differ in terms of _____.
effect size
Two studies were conducted to compare the academic performance of men and women, using two different tests. One study reports d = 0.23, and the other reports d = 0.52. Based on this information, these two studies differ in terms of:
effect size.
For random samples of size 100 from a population, the mean of the sample means from all possible samples is _____ the population mean.
equal to
The only practical difference between conducting a z test with a z distribution and conducting a t test with a t distribution is _____ the standard deviation.
estimating
A study comparing one group of participants who are randomly assigned to receive a drug with another group of participants who are randomly assigned to receive a placebo is an example of a(n) _____ that has a _____ research design.
experiment; between-groups
When designing an experiment, the group that receives the treatment or intervention is known as the:
experimental group.
Random assignment to a condition or level of one or more independent variables is the hallmark of:
experimental research.
After conducting a paired-samples t test, if the test statistic is greater than the lower cutoff and less than the upper cutoff, the researcher should _____ the null hypothesis.
fail to reject
Dr. Huang compares working memory span in 16-year-olds and adults. Her data does not suggest a difference between the two groups. She should _____ the null hypothesis.
fail to reject
Greta conducts a study comparing the performance of individuals in two different statistics classes who have taken the same quiz. The scores, out of 100, are provided for individuals in each group. Class 1: 87, 78, 87, 85, 93, 98, 83, 82, and 73 Class 2: 87, 86, 92, 90, 90, 91, 89, 78, and 76 Given a two-tailed test and a p level of 0.01, based on the value of the t statistic, Greta should _____ the null hypothesis when _____.
fail to reject; p >0.01
If a researcher does not find support for her research hypothesis, she _____ the null hypothesis.
fails to reject
Dr. Hyde is conducting an experiment to compare the effects of two different drugs on anxiety: a new drug and a drug that has been established as effective for some time. To randomly assign 100 individuals to conditions she can:
flip a coin, assigning those who get heads to one condition and those who get tails to another condition.
Pascal, a researcher, is interviewing a group of bicyclists and recording how many races they won during the previous season. He does not want to use a graph but does want to display how often each number of wins occurred. He should use a(n) _____ table.
frequency
Tommy, a researcher, is interviewing a group of bicyclists and recording how many races they won during the previous season. He does not want to use a graph, but he does want to display how often each number of wins occurred. He should use a:
frequency table.
It is typically okay to violate the assumption about random selection of participants if one is cautious about _____.
generalizing
A population distribution is very left skewed with mean µ = 40 and standard deviation s = 10. Consider two sampling distributions from this population distribution. Sampling distribution #1 is created from the sample means of all possible random samples of size N = 9; sampling distribution #2 is created from the sample means of all possible random samples of size 81. The standard deviation of sampling distribution #1 is _____ the standard deviation of sampling distribution #2.
greater than
If one wants to visually report frequencies for data that have many decimal places, it is BEST to use a _____ frequency table.
grouped
On Eli's math test, both Professor Jameson and Professor Alley assign a grade of A. Using this measure to determine Eli's math class placement would have:
high reliability and high validity.
A(n) _____ provides frequencies for scale data using bars.
histogram
Dr. Phillips is interested in whether study techniques are related to a student's major in college. To study this, she recruits 20 students from each major on campus to participate in her study and then uses this information to draw conclusions about the population of interest. This exemplifies:
hypothesis testing
Dr. Reno is interested in whether study techniques are related to a student's major in college. To study this, she recruits 20 students from each major on campus to participate in her study and then uses this information to draw conclusions about the population of interest. This exemplifies _____.
hypothesis testing
With which statistics-based process do social scientists test their ideas?
hypothesis testing
_____ can be broken down into six standard steps.
hypothesis testing
A(n) _____ variable is any variable that has at least two levels and that can be manipulated to determine its effects on the dependent variable.
independent
The National Park Service (NPS) is interested in comparing the amount of money that visitors in two different national parks spend. It samples the visitors on the same day in each of the two parks and then compares the mean dollar amounts spent from each sample. Analysis for these data will be based on a(n) _____-samples test.
independent
Two events are _____ if knowing one has occurred gives no additional information about whether the second will occur.
independent
The National Park Service (NPS) is interested in comparing the amount of money that visitors in two different national parks spend. It samples the visitors on the same day in each of the two parks and then compares the mean dollar amounts spent from each sample. Analysis for these data will be based on:
independent samples.
Aaron and Dana are conducting an experiment to determine whether temperature influences learning. They train 20 rats to press a lever in an operant chamber to receive food pellets. For one group of 10 rats the ambient temperature in the room during each session is held constant at 70 degrees Fahrenheit, and for the remaining group of 10 rats the temperature during each session is held constant at 85 degrees Fahrenheit. For the group that experiences the 70 degrees Fahrenheit condition, 80 percent of the rats emit more than one response per second in each one-hour session. For the group that experiences the 85 degrees Fahrenheit condition, 50 percent of the rats emit more than one response per second in each one-hour session. Aaron and Dana estimate that 80 percent of all rats trained on this task in 70 degrees Fahrenheit temperature would emit more than one response per second. Based on the information provided, 80 percent is being used as a(n):
inferential statistic
Harriet conducts a study comparing the performance of biology majors and psychology majors taking the same introductory psychology quiz. The scores, out of 100, are provided for individuals in each group. Biology majors: 87, 78, 77, 85, 83, 88, and 73 Psychology majors: 87, 96, 92, 90, 90, and 91 According to conventions for Cohen's d, the effect size for this study is _____.
large
Raul conducts a study comparing the performance of biology majors and psychology majors taking the same introductory psychology quiz. The scores, out of 100, are provided for individuals in each group. Biology majors: 87, 78, 77, 85, 83, 88, and 73 Psychology majors: 87, 96, 92, 90, 90, and 91 Given s2pooled = 21.428, according to conventions for Cohen's d, the effect size for this study is: Please choose the correct answer from the following choices, and then select the submit answer button.
large
The following histogram gives the distribution of the year-minted for 600 pennies collected by students. The shape of the distribution of data in this histogram is _____.
left-skewed
In a pre-election poll, surveyors want to assess the opinions of:
likely voters.
Histograms organize the many intervals occurring along the x-axis by arranging _____ numbers on the left and _____ numbers on the right.
low, high
When conducting a paired-samples t test, the comparison distribution is a distribution of:
mean difference scores.
When conducting a paired-samples t test, because the null hypothesis posits no difference between the populations, the comparison distribution is a distribution of:
mean differences with a mean of 0.
When figuring out financial aid packages, financial aid offices are interested in studying how much a student might reasonably be able to earn. A simple random sample of students at one university in southern Georgia was interviewed about how much money they earn each month. The resulting 95 percent confidence interval was ($150.75, $223.74) for those with part-time jobs. On what sample estimate was the confidence interval based?
mean monthly earnings for students sampled with part-time jobs at that university
Consider a study testing the hypothesis that, on average, individuals who take a new drug will remember fewer words in a recall memory test than those in the population. Given this information, the effect size is _____ according to Cohen's conventions for effect sizes.
medium
Most of the scores in a normal curve are clustered in the _____.
middle
Grouped frequency tables can be converted into histograms by listing the _____ of each interval on the x-axis.
midpoint
Acme Ice Cream Company conducted a survey. The survey asked about their customers' emotional state when eating ice cream. The most common response to the survey question was "very happy." In other words, "very happy" was the _____ answer given.
modal
A ninth-grade math test is given to a group of third-graders. The scores are not expected to be normally distributed because:
most of the scores should fall at the extreme low end of the distribution.
A group of statistics students have taken a test. When their teacher, Professor Toms, graphs their scores using a frequency polygon, he notices that very few students scored poorly on the test. Rather, a majority of students achieved a score of 90 percent or higher. This trend could be described as a(n) _____ distribution.
negatively skewed
Many manufacturers conduct focus groups and do surveys to find out what consumers want in a product. They are also interested in determining what type of packaging will entice shoppers to buy their products. Brand Z cereal is thinking about changing the package design to make it more attractive so that shoppers will buy it on impulse. Changing packaging is expensive, however, so they want to be certain that the new package design will be successful in attracting impulse shoppers. In this scenario, a Type II error is:
not changing the package design when it would help sell their cereal.
A _____-tailed z test is used when the study is that the mean will be higher or lower than that of the population.
one
If the symbol ≤ is found in the null hypothesis, one will declare the test to be _____-sided.
one
If the symbol ≥ is found in the null hypothesis, one will declare the test to be _____-sided.
one
Whenever the symbol > is found in the research hypothesis, one will declare the test to be _____-sided.
one
The average IQ score among adults is 100. Because the average describes all adults, the number 100 is a(n) _____.
parameter
Finding a score's _____ is the same as finding the percentage of z scores that fall below the score.
percentile rank
For a two-sample, between-groups design, the formula for effect size is similar to that for the test statistic in an independent-samples t test, except that calculating effect size involves dividing by the:
pooled standard deviation, rather than the standard error.
A requirement of the inference methods is that the _____ should have a normal distribution.
population
In a negatively skewed distribution, the majority of responses are clustered on the _____ end of the distribution.
positive
A(n) _____ skewed distribution has one tail that pulls to the right.
positively
Dr. Budd is conducting a study to examine the efficacy of a new intervention to increase self-esteem in teenage girls. Which expression addresses the extent to which she can feel confident that she has the ability to reject the null hypothesis given it is in fact false?
power > 0.80
A(n) _____ ensures that each participant in a study has an equal chance of being assigned to any level of the independent variable.
random assignment
A data set includes the following scores: 1, 1, 2, 2, 5, 6, 10, 10, 14, 15, 15, and 20. Then, 20 (the highest score) - 1(the lowest score) would be an example of:
range
The _____ is the easiest measure of variability to calculate.
range
When creating a grouped frequency table, it is possible to determine the most appropriate number of intervals by dividing the _____ by the number of intervals one wants, and rounding to the nearest whole number.
range
Dr. Washington is interested in studying the relationship between test scores, coded from zero to 100 percent, and number of hours of studying for the test by college students. In this example, test score is a(n) _____ variable.
ratio
If the value of the independent t statistic is outside the span of scores bound by the critical values, the researchers should _____ the null hypothesis.
reject
When Dr. Ogawa studied the effect of toddlers' style of attachment with their parents on the toddlers' problem-solving ability, he found that the toddlers who have a secure attachment style have better problem-solving abilities than those who have an insecure attachment style. He should:
reject the idea that there is no difference between the securely and insecurely attached toddlers.
A _____ hypothesis test is one that produces fairly accurate results even when the data suggest that the population might not meet some of the assumptions.
robust
If an assumption about the population is not met, but the results of the testing are fairly accurate, the testing is then referred to as:
robust hypothesis testing
Dr. Farmington is interested in the political attitudes of male college students. He sends an e-mail message to all of the men enrolled at the three local community colleges in which he asks for volunteers to participate in a study. He receives replies from 138 men who sign up to participate. On the day of the study, 78 men show up and complete the study. In this example, the 78 men constitute a(n):
sample
In statistics, the _____ is made up of the individuals from whom information is gathered.
sample
The t statistic is the distance of a _____ from a _____ in terms of the estimated standard error.
sample mean; population mean
Inferential statistics use _____ data to make general estimates about the _____.
sample; population
Because it is rarely possible to study every person or organization or thing in a particular population, _____ are often used.
samples
A histogram shows the overall pattern, or _____ of the distribution of data.
shape
Hypothesis testing can be broken down into _____ standard steps.
six
A nonsymmetrical grouping of scores is also defined as a(n) _____ distribution.
skewed
Which term describes distributions that are not normally distributed?
skewed
Francesca conducts a study comparing the performance of individuals in two different statistics classes taking the same quiz. The scores, out of 100, are provided for individuals in each group. Class 1: 87, 78, 87, 85, 93, 98, 83, 82, and 73 Class 2: 87, 86, 92, 90, 90, 91, 89, 78, and 76 According to conventions for Cohen's d, the effect size for this study is:
small
Raul conducts a study to compare the performance of students of two classes on a quiz taken during the first term of their freshman year. The scores, out of 100, are provided for nine individuals in both classes. Class 1: 87, 78, 87, 85, 93, 98, 83, 82, and 73 Class 2: 87, 86, 92, 90, 90, 91, 89, 78, and 76 Given s = 5.175. According to conventions for Cohen's d, the effect size for this study is:
small.
Two studies were conducted to compare the academic performance of men and women, using two different tests. A study that reports d = 0.23 has a _____ effect size, and a study that reports d = 0.82 has a _____ effect size.
small; large
A z test can only be conducted when there is one sample and both the mean and the _____ are known for the population.
standard deviation
One can conduct a t test instead of a z test when one has to estimate the population _____.
standard deviation
If a z score is negative and one wants to find the percentage of scores that fall below that score, one would first look up the z score, find the "percent between mean and z" column of the standard normal table, and then:
subtract the value in the table from 50 percent.
Individuals who believe in psychic abilities are more likely to remember the one thing that a famous psychic correctly predicted for 2015 and forget his 25 incorrect predictions due to:
the confirmation bias.
Central tendency is BEST defined as:
the descriptive statistic that best represents the center of a data set.
A meta-analysis involves the calculation of a mean effect size from:
the individual effect sizes in many studies.
When a statistician talks about a sample, he or she is referring to:
the individuals from whom information was gathered.
A psychology professor tells her class to read a particular research article. The abstract for the article starts with, "In this experiment . . ." and goes on to provide a brief summary of the study. From this, one can be sure that:
the participants were randomly assigned to conditions.
The difference in calculating the effect size in a single-sample t test and a z test is that the effect size is calculated using:
the population standard deviation instead of the population standard error.
Which of the probabilities below describe a pair of events that are independent?
the probability that a randomly selected college student was in their high school band and the probability that the student owns a smart phone
The probability of randomly selecting a college student who was involved in high school athletics is 17%. Which of these events would NOT be independent of this probability?
the probability that the student is involved in college athletics
Dr. Hancock conducts a study testing whether a new drug developed to treat general anxiety disorder works better than the usual treatment of cognitive behavioral therapy (CBT). The participants are randomly assigned to either the drug therapy or the CBT. After 4 weeks of treatment, all of the participants complete the General Anxiety Test (GAT). The data reveal that the participants in the drug therapy have lower GAT scores (i.e., less anxiety) than those who participated in CBT. Dr. Hancock concludes that the new drug has a more effective result. In this study, the independent variable is:
treatment
A ruler being used to measure intelligence would be a measure with questionable _____.
validity
In a _____ research design, all participants experience different levels of the independent variable.
within-groups
