Question 1

A correlation coefficient of zero describes

Accepted Answer

A correlation coefficient of zero indicates that there is no relationship between two variables. It does not indicate a positive or negative relationship, and it is not a perfect relationship.

Question 2

Dr Ahmed predicts that people will act more aggressively during the heat waves of summer than they will during the cold spells of winter. This suggests that Dr Ahmed believes that temperature and level of aggression are

Accepted Answer

Dr Ahmed predicts a positive correlation between temperature and level of aggression, meaning as temperature increases, level of aggression is expected to increase as well.

Question 3

Which of the following statements about correlations is incorrect?

Accepted Answer

Correlation does not imply causation. Just because two variables are correlated (in this case, with a correlation coefficient of +1.00) does not mean that one caused the other. Other outside factors may be responsible.

Question 4

A correlation between two variables exists when scores on one variable

Accepted Answer

A correlation between two variables exists when there is a relationship between the scores on one variable and the scores on the second variable. This means that as the scores on one variable change, the scores on the second variable also change in a predictable way. The correlation may be positive (meaning the scores on both variables increase or decrease together) or negative (meaning one variable increases while the other decreases). However, correlation does not necessarily imply causation, which would be choice B.

Question 5

If we were to measure the height and weight of 100 adult women, we would find that these two measures are

Accepted Answer

Height and weight are generally positively correlated in adults, meaning that as height increases, weight tends to increase as well. Therefore, the best choice is D) positively correlated.

Question 6

Dr Abrahams has found that students who score higher than 85% on the first midterm tend to earn scores of 75% or better on the final exam, while students who score less than 60% on the first midterm often end up with a failing grade on the final exam. This suggests that

Accepted Answer

The statement suggests that there is a positive correlation between the scores on the first midterm and the final exam. Students who score higher on the first midterm tend to do better on the final exam, while those who score lower on the first midterm tend to do worse on the final exam.

Question 7

As an adult ages, his/her physical strength declines. The relationship between age and physical strength is a(n)

Accepted Answer

The relationship between age and physical strength is a negative correlation because as age increases, physical strength declines.

Question 8

The ____ is an index of the amount of variability in a set of data.

Accepted Answer

The standard deviation measures the spread of data around the mean, indicating the amount of variability in the data set. Statistical significance refers to the likelihood of obtaining a result by chance, central tendency refers to the typical or average value of a data set, and correlation coefficient measures the strength of the relationship between two variables. None of these options provide an index of variability.

Question 9

A correlation coefficient will always have a value between

Accepted Answer

Correlation coefficients range from -1.00 to +1.00, indicating the strength and direction of the relationship between two variables. A value of -1.00 indicates a perfect negative correlation, 0 indicates no correlation, and +1.00 indicates a perfect positive correlation.

Question 10

The correlation coefficient is a measure of

Accepted Answer

The correlation coefficient is a measure of the degree of relationship between two variables. It tells us how closely two variables are related and the direction of the relationship (positive or negative). It ranges from -1 (perfect negative correlation) to 1 (perfect positive correlation), with 0 indicating no correlation. The correlation coefficient does not measure central tendency or variability in a data set, nor does it measure the difference between the largest and smallest scores.

Question 11

Suppose a researcher discovered a +0.87 correlation between the length of a person's toes and the number of shoes the person owns. In general, people who own the fewest number of shoes would have

Accepted Answer

A positive correlation of +0.87 indicates a strong relationship where, as the length of a person's toes increases, the number of shoes they own also tends to increase. Therefore, people who own the fewest number of shoes would likely have smaller toes.

Question 12

The FDA found that people who used a particular diet drug combination had more heart valve defects than people who had not taken the diet drug combination. This suggests that the use of the diet drug combination and heart valve defects are

Accepted Answer

The fact that people who used the diet drug combination had more heart valve defects than those who had not suggests that there is a positive correlation between the two variables. This means that the more someone uses the diet drug combination, the more likely they are to have heart valve defects.

Question 13

As the number of bystanders' increases, people are less likely to help someone who is in distress. This suggests that the size of a crowd and helping behaviour are

Accepted Answer

The statement suggests a negative correlation between the size of a crowd and helping behavior, meaning that as the number of bystanders increases (size of the crowd), the likelihood of someone helping decreases.

Question 14

Dr Reddy has found a correlation of +0.65 between snoring and weight. This indicates that

Accepted Answer

A correlation of +0.65 indicates a positive relationship between weight and snoring. Therefore, overweight individuals tend to snore more than underweight individuals.

Question 15

A high correlation coefficient (either positive or negative) indicates that

Accepted Answer

A high correlation coefficient indicates that there is a high level of consistency between the two variables. This means that as one variable increases, the other variable tends to increase (positive correlation) or decrease (negative correlation) as well. However, it does not necessarily mean that one variable directly causes a change in the other variable or that a third factor is responsible for the relationship.

Question 16

Dr Molefe surveys 50 university students to discover the relationship between textbook price and ratings of readability. Dr Molefe finds that for these two variables the correlation coefficient is -0.70. This indicates that

Accepted Answer

The negative correlation coefficient of -0.70 indicates that as textbook price increases, ratings of readability tend to decrease. Therefore, more expensive books tend to receive lower readability ratings than less expensive books.

Question 17

As interest rates increase, house sales decline, indicating

Accepted Answer

The increase in interest rates has a negative effect on house sales, meaning that as one variable increases, the other decreases. This indicates a negative correlation between the two variables.

Question 18

If two variables have a positive correlation, you would expect that ____ scores on one variable are generally associated with ____ scores on the second variable.

Accepted Answer

A positive correlation means that as values in one variable increase, values in the other variable also increase, and vice versa.

Question 19

Suppose a researcher discovered a strong negative correlation between the length of people's hair and the amount of money they paid for their automobile. In general, people who paid the least amount of money for their automobile also had

Accepted Answer

A strong negative correlation means that as one variable increases, the other decreases. Therefore, if the amount paid for an automobile decreases, the length of hair increases, indicating those who paid the least have the longest hair.

Question 20

Of the following, the correlation coefficient that indicates the weakest relationship between the two variables being measured is

Accepted Answer

A correlation coefficient of +0.01 indicates a very weak or negligible relationship between the two variables being measured. A correlation coefficient of +0.95 indicates a very strong positive relationship, while a correlation coefficient of -0.69 indicates a moderately strong negative relationship. The value of -4.50 is not a valid correlation coefficient as it falls outside the range of -1 to +1.

Quiz 2: Research Methods in Psychology