Interpreting Results - AP Psychology
Card 0 of 20
The following test scores were obtained by students in Mr. Verbino's math class:
Which of the following statements about the above dataset is true?
The following test scores were obtained by students in Mr. Verbino's math class:
Which of the following statements about the above dataset is true?
The mean (82.8) is greater than the median (81) because the very high score of 102 weighs more heavily in the mean calculation.
The mean (82.8) is greater than the median (81) because the very high score of 102 weighs more heavily in the mean calculation.
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What kind of statistical test would be used to determine if there is a linear relationship between two variables?
What kind of statistical test would be used to determine if there is a linear relationship between two variables?
A Pearson correlation between two variables indicates that as one variable increases, another variable either increases or decreases by some amount in a linear manner.
A Pearson correlation between two variables indicates that as one variable increases, another variable either increases or decreases by some amount in a linear manner.
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A study finds a strong negative correlation between the amount of chocolate a child consumes and the number of absences the child has from school. Which of the following values could express that correlation?
A study finds a strong negative correlation between the amount of chocolate a child consumes and the number of absences the child has from school. Which of the following values could express that correlation?
Correlations range between 
and 
, with 
signifying the strongest possible negative correlation between two variables, 
signifying the strongest possible positive correlation, and 
signifying the complete absence of any correlation between two variables.
Correlations range between
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Which of these represents the strongest correlation coefficient?
Which of these represents the strongest correlation coefficient?
Correlation coefficients range from -1 to 1, with the strongest correlations being closer to -1 or 1. A correlation of 0 indicates no relationship between two variables. Negative correlations can be as strong or stronger than positive correlations; the most important factor is the magnitude of the correlation.
Correlation coefficients range from -1 to 1, with the strongest correlations being closer to -1 or 1. A correlation of 0 indicates no relationship between two variables. Negative correlations can be as strong or stronger than positive correlations; the most important factor is the magnitude of the correlation.
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What is an illusory correlation?
What is an illusory correlation?
An illusory correlation occurs when someone thinks that two variables are related, but they are actually not (they have a correlation of 0).
An illusory correlation occurs when someone thinks that two variables are related, but they are actually not (they have a correlation of 0).
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Which term refers to the middle term in a distribution of data?
Which term refers to the middle term in a distribution of data?
The median is the middle number in a data set. For example, the median of {3, 7, 4, 5, 8} is 5. The terms must first be placed in increasing order: {3, 4, 5, 7, 8}. From here, it becomes evident that 5 is the middle term, or median.
The median is the middle number in a data set. For example, the median of {3, 7, 4, 5, 8} is 5. The terms must first be placed in increasing order: {3, 4, 5, 7, 8}. From here, it becomes evident that 5 is the middle term, or median.
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Which of the following is an appropriate definition for statistics?
Which of the following is an appropriate definition for statistics?
Statistics play a big role in much of the research in the field of psychology. In studying groups of people and individuals, their behaviors, reactions, etc. a researcher will have lots of numerical data on their hands. Statistics is the analysis of this numerical data.
Statistics play a big role in much of the research in the field of psychology. In studying groups of people and individuals, their behaviors, reactions, etc. a researcher will have lots of numerical data on their hands. Statistics is the analysis of this numerical data.
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Carol did a study examining the link between male students' test scores and their alcohol consumption. Other researchers replicated her study in a similar setting and got back similar results, but argued that her study answers a different question than it was designed to answer.
Carol's study is __________.
Carol did a study examining the link between male students' test scores and their alcohol consumption. Other researchers replicated her study in a similar setting and got back similar results, but argued that her study answers a different question than it was designed to answer.
Carol's study is __________.
A study's validity is its ability to scientifically measure the concepts it was designed to measure. A study's reliabilityis its ability to yield similar results when replicated in a similar setting.
Because Carol's study could be replicated but does not answer the question it was designed to answer her study is reliable, but not valid.
A study's validity is its ability to scientifically measure the concepts it was designed to measure. A study's reliabilityis its ability to yield similar results when replicated in a similar setting.
Because Carol's study could be replicated but does not answer the question it was designed to answer her study is reliable, but not valid.
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In a correlation experiment which number shows the weakest correlation?
In a correlation experiment which number shows the weakest correlation?
The number describing two variables relationship is the correlation coefficient. This could show a positive correlation (+ number) or a negative correlation (- number). The further from 0 the coefficent is the stronger the correlation.
The number describing two variables relationship is the correlation coefficient. This could show a positive correlation (+ number) or a negative correlation (- number). The further from 0 the coefficent is the stronger the correlation.
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When measuring central tendency, which of the following choices is known to be biased depending on the data set?
When measuring central tendency, which of the following choices is known to be biased depending on the data set?
The mean is the average of a data set. On the other hand, the median is considered to be the 50th percentile—that is cutting the entire data set in half and representing the exact middle of the data set. The mean may be skewed depending on the data set. For instance, the median may be 50 but because of a few higher numbers, the mean could be 56. Using the mean as a measure of central tendency may cause the distribution to be a bit lopsided. Percent error is a statistical measure of the marginal error of actual results compared to expected results; therefore, percent error would not be the correct answer. Additionally, standard deviation is the measurement of the deviation from a group as a whole. This calculation is often conducted using averages (means); thus, the options standard deviation and standard deviation of the mode would also be incorrect.
The mean is the average of a data set. On the other hand, the median is considered to be the 50th percentile—that is cutting the entire data set in half and representing the exact middle of the data set. The mean may be skewed depending on the data set. For instance, the median may be 50 but because of a few higher numbers, the mean could be 56. Using the mean as a measure of central tendency may cause the distribution to be a bit lopsided. Percent error is a statistical measure of the marginal error of actual results compared to expected results; therefore, percent error would not be the correct answer. Additionally, standard deviation is the measurement of the deviation from a group as a whole. This calculation is often conducted using averages (means); thus, the options standard deviation and standard deviation of the mode would also be incorrect.
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A researcher has determined through an experiment that moderate doses of ginseng have no effect on verbal memory; thus, he fails to reject the null hypothesis. In reality, the researcher missed a critical data point in his analysis that should have pointed towards a positive effect of ginseng on memory. This is an example of which of the following types of research error?
A researcher has determined through an experiment that moderate doses of ginseng have no effect on verbal memory; thus, he fails to reject the null hypothesis. In reality, the researcher missed a critical data point in his analysis that should have pointed towards a positive effect of ginseng on memory. This is an example of which of the following types of research error?
Type II error—also called a false negative—occurs when a researcher incorrectly fails to reject a false null hypothesis. In other words, the researcher should have rejected the null hypothesis in favor of the experimental hypothesis. In this case, the researcher should have found evidence in favor of the experimental hypothesis that ginseng consumption has a significant effect on memory; however, the researcher failed to do so because of some experimental error (i.e. random or systematic, the problem does not specify).
Type II error—also called a false negative—occurs when a researcher incorrectly fails to reject a false null hypothesis. In other words, the researcher should have rejected the null hypothesis in favor of the experimental hypothesis. In this case, the researcher should have found evidence in favor of the experimental hypothesis that ginseng consumption has a significant effect on memory; however, the researcher failed to do so because of some experimental error (i.e. random or systematic, the problem does not specify).
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IQ data is collected for one thousand individuals. If the data are normally distributed, how many of these individuals are likely to fall within two standard deviations above the mean?
IQ data is collected for one thousand individuals. If the data are normally distributed, how many of these individuals are likely to fall within two standard deviations above the mean?
2.3 percent of individuals fall two standard deviations above the mean in a normal distribution. 2.3% of 1000 individuals is 23 individuals that fall above this cutoff.
Convert the percentage into a ratio.
Create a ratio using the total number of the sample size. Use the variable 
as a representation of the number of individuals that fall two standard deviations above the mean.
Create a proportion using the two ratios.
Cross multiply and solve for 
.
Simplify.
Divide both sides of the equation by 
.
Solve.
2.3 percent of individuals fall two standard deviations above the mean in a normal distribution. 2.3% of 1000 individuals is 23 individuals that fall above this cutoff.
Convert the percentage into a ratio.
Create a ratio using the total number of the sample size. Use the variable
Create a proportion using the two ratios.
Cross multiply and solve for
Simplify.
Divide both sides of the equation by
Solve.
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Researchers discover a .62 correlation between self-esteem and academic achievement in a group of high school students. This would be described as a __________ in strength relationship.
Researchers discover a .62 correlation between self-esteem and academic achievement in a group of high school students. This would be described as a __________ in strength relationship.
Any correlation between .30 and .69 is considered moderate in strength. Anything above .60 is considered strong. Anything below .30 is considered weak or no correlation.
Any correlation between .30 and .69 is considered moderate in strength. Anything above .60 is considered strong. Anything below .30 is considered weak or no correlation.
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A group of psychologists reject their null hypothesis, but it turns out that their null hypothesis is true. What kind of error have they committed?
A group of psychologists reject their null hypothesis, but it turns out that their null hypothesis is true. What kind of error have they committed?
A type I error occurs when a null hypothesis is rejected when researchers should have failed to reject the null hypothesis, in other words, when the researchers reject a true hypothesis. Remember, a null hypothesis is the assumption that there is no difference between the groups participating in the study. So if a type I error occurs, that means that the researchers are stating there is a difference between the groups when there really is not a difference. A Type II error involves the acceptance of a false hypothesis.
A type I error occurs when a null hypothesis is rejected when researchers should have failed to reject the null hypothesis, in other words, when the researchers reject a true hypothesis. Remember, a null hypothesis is the assumption that there is no difference between the groups participating in the study. So if a type I error occurs, that means that the researchers are stating there is a difference between the groups when there really is not a difference. A Type II error involves the acceptance of a false hypothesis.
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A group of psychologists fail to reject their null hypothesis, but the null turns out to be false. What kind of error have they committed?
A group of psychologists fail to reject their null hypothesis, but the null turns out to be false. What kind of error have they committed?
A type II error occurs when researchers fail to reject their null hypothesis when they should have rejected it. A null hypothesis is the assumption that there is no difference between the groups being studied. So if a type II error occurs, that means that the researchers are stating there is not a difference between the groups when there really is one.
A type II error occurs when researchers fail to reject their null hypothesis when they should have rejected it. A null hypothesis is the assumption that there is no difference between the groups being studied. So if a type II error occurs, that means that the researchers are stating there is not a difference between the groups when there really is one.
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A psychology statistics professor wants to display data from previous test scores. There are 100 students in her class. On the last test 5 students received perfect scores; however, the rest of the students averaged a score of a 66. Which of the following central tendency measures would be the best to describe the class’s performance on the exam?
A psychology statistics professor wants to display data from previous test scores. There are 100 students in her class. On the last test 5 students received perfect scores; however, the rest of the students averaged a score of a 66. Which of the following central tendency measures would be the best to describe the class’s performance on the exam?
Central tendency measures include the mean, median, and mode. In this case, the median would be best because several outliers skew this data set (e.g. perfect scores). The mean would be influenced strongly by these outliers.
Central tendency measures include the mean, median, and mode. In this case, the median would be best because several outliers skew this data set (e.g. perfect scores). The mean would be influenced strongly by these outliers.
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Which of the following correlation coefficients demonstrates a strong inverse relationship?
Which of the following correlation coefficients demonstrates a strong inverse relationship?
A correlation coefficient is a measure of the relationship between two variables. Correlation coefficients range from -1 to +1. For this reason -1.5 is incorrect because it is not possible to have a correlation coefficient less than -1. This question is asking for a coefficient with a strong inverse relationship. A positive number indicates a direct relationship, while a negative number indicates an indirect or inverse relationship. The specific number indicates the strength of the relationship. If the correlation coefficient is closer to -1 or +1, then it is said to be strong. As the number moves closer to zero, the strength of the relationship decreases; therefore, -0.90 is the best answer.
A correlation coefficient is a measure of the relationship between two variables. Correlation coefficients range from -1 to +1. For this reason -1.5 is incorrect because it is not possible to have a correlation coefficient less than -1. This question is asking for a coefficient with a strong inverse relationship. A positive number indicates a direct relationship, while a negative number indicates an indirect or inverse relationship. The specific number indicates the strength of the relationship. If the correlation coefficient is closer to -1 or +1, then it is said to be strong. As the number moves closer to zero, the strength of the relationship decreases; therefore, -0.90 is the best answer.
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The following are the ages of 12 children sitting in a row at an elementary school assembly:
For the data set, what are the mean, median, and mode, respectively?
The following are the ages of 12 children sitting in a row at an elementary school assembly:
For the data set, what are the mean, median, and mode, respectively?
In order to calculate the mean (also called arithmetic average) we need to add all the values together and divide by the number of values. In this case, the total sum is 87 and the number of values is 12, so we perform the following calculation to obtain our mean:
To find the median, we simply arrange the values in order from least to greatest and identify the middlemost number. However, since 12 is an even number, there will not be one single middle value– therefore, we find the average of the two middlemost values. Arranged in ascending order, the data set is:
The 6th and 7th values are 6 and 7, so we know our median is the average of 6 and 7.
The mode is the value that occurs most frequently in the data set. Here, 6 occurs three times and no other number occurs more than twice, which means 6 is our mode.
In order to calculate the mean (also called arithmetic average) we need to add all the values together and divide by the number of values. In this case, the total sum is 87 and the number of values is 12, so we perform the following calculation to obtain our mean:
To find the median, we simply arrange the values in order from least to greatest and identify the middlemost number. However, since 12 is an even number, there will not be one single middle value– therefore, we find the average of the two middlemost values. Arranged in ascending order, the data set is:
The 6th and 7th values are 6 and 7, so we know our median is the average of 6 and 7.
The mode is the value that occurs most frequently in the data set. Here, 6 occurs three times and no other number occurs more than twice, which means 6 is our mode.
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In an experiment, which of the following is measured or recorded by the experimenter?
In an experiment, which of the following is measured or recorded by the experimenter?
The "dependent variable" is indicative of the outcome of an experiment, and is recorded as evidence to attempt to provide support for or against a thesis. The independent variable is indeed measured; however,its quantities are irrelevant to an experiment. Control and random variables are not recorded and are only useful when considering the changes to dependent variable.
The "dependent variable" is indicative of the outcome of an experiment, and is recorded as evidence to attempt to provide support for or against a thesis. The independent variable is indeed measured; however,its quantities are irrelevant to an experiment. Control and random variables are not recorded and are only useful when considering the changes to dependent variable.
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Which of the following correlation coefficients indicates the strongest relationship?
Which of the following correlation coefficients indicates the strongest relationship?
A correlation coefficient is a statistical measure of the extent to which two factors vary together. Specifically, it measures how well one factor predicts another on a scale of -1 to 1, with numbers closer to -1 and 1 indicating the strongest relationships. Whether a correlation coefficient is negative or positive does not indicate the strength of the relationship, it simply tells us the direction of the relationship!
A correlation coefficient is a statistical measure of the extent to which two factors vary together. Specifically, it measures how well one factor predicts another on a scale of -1 to 1, with numbers closer to -1 and 1 indicating the strongest relationships. Whether a correlation coefficient is negative or positive does not indicate the strength of the relationship, it simply tells us the direction of the relationship!
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