Question 1

Raw data are data that have not yet been analyzed.

Accepted Answer

Raw data refers to data that has been collected but not yet analyzed or processed.

Question 2

What is plotted on the Y-axis of a histogram?

Accepted Answer

The Y-axis of a histogram represents the frequency of each score or bin of scores in the distribution.

Question 3

There is a statistical relationship between two variables if which of the following is true?

Accepted Answer

A statistical relationship between two variables exists if the average level of one variable differs across levels of the other. This is known as a correlation, which measures the strength and direction of the relationship between two variables. The other options (A, B, and D) do not necessarily indicate a statistical relationship between two variables.

Question 4

It is impossible to say what the results of a study are until the inferential statistics have been done.

Accepted Answer

The results of a study can be described using descriptive statistics, which summarize the data collected, even before inferential statistics are applied to make generalizations or predictions.

Question 5

In psychological research, which of the following is considered a strong relationship?

Accepted Answer

In psychological research, a correlation coefficient of r = .50 is considered a strong relationship. The other options have effect sizes that could be considered small (d = 0.20), moderate (d = 0.50), or weak (r = -.30).

Question 6

In a computer data file, each participant is usually represented by a column of data.

Accepted Answer

In a computer data file, each participant is usually represented by a row of data, with the columns representing different variables or attributes.

Question 7

If Esther has a z score of -0.10 on a test of reading ability, which of the following is true?

Accepted Answer

A z score of -0.10 indicates that Esther's reading ability is close to average, as the mean z score is 0 and one standard deviation is 1. Therefore, options A, C, and D are incorrect.

Question 8

In a positively skewed distribution, which of the following is true?

Accepted Answer

In a positively skewed distribution, there are a few extreme values that are much greater than the majority of the values. This pulls the mean toward the right, making it larger than the median.

Question 9

Conceptually, what is the standard deviation?

Accepted Answer

The standard deviation is the measure of the variability or spread of a set of scores in a distribution. It tells us how much the individual scores deviate, on average, from the mean or central tendency of the distribution. Hence, option A is the correct interpretation of the standard deviation.

Question 10

Researchers should avoid using their data to answer questions that they had not planned on answering when they conceptualized the study.

Accepted Answer

Exploratory analysis of data can lead to new insights and hypotheses, which can be valuable for further research, as long as the limitations and exploratory nature of the findings are clearly communicated.

Question 11

The mean score on a test of agreeableness is 27 with a standard deviation of 8. Rudolfo got a score of 25 on this test. What is his z score?

Accepted Answer

The z score is calculated by subtracting the mean from the individual score and then dividing by the standard deviation: $z = \frac{(25 - 27)}{8} = \frac{-2}{8} = -0.25$.

Question 12

Nora likes to eat her lunch at a different fast food restaurant every day, so the amount she spends for lunch per day is a variable. Which of the following would be a reasonable estimate of the standard deviation of this variable?

Accepted Answer

Since Nora eats at a different fast food restaurant every day, it is reasonable to assume that the cost of her lunch would vary within a certain range. A standard deviation of $1 would account for this variability without being too large or too small. Choices A and C are too small and do not take into account the possible range of costs Nora may encounter. Choice D is too large and assumes a much wider range of costs than is likely.

Question 13

Jane computes the variance for a set of data and gets the correct answer of 16. What is the standard deviation for this same set of data?

Accepted Answer

The answer of Jane computes the variance for a set...

Question 14

On a research methods exam, most of the students did well but a few did poorly. Which of the following is most clearly true?

Accepted Answer

When most students score well and a few score poorly, the distribution of scores is positively skewed, meaning the tail is on the right side.

Question 15

Complex sets of data are likely to include "patterns" that occurred entirely by chance.

Accepted Answer

This is true as random events can sometimes appear to have patterns or correlations within larger sets of data. However, it is important to use statistical analysis to determine whether these patterns are actually significant or merely coincidental.

Question 16

Which of the following represents the strongest statistical relationship?

Accepted Answer

A) d = 0.80 represents the strongest statistical relationship because it indicates a large effect size, whereas the other options represent correlation coefficients, which are weaker in comparison.

Question 17

Which of the following measures of central tendency can be used for a categorical variable?

Accepted Answer

The mode is the only measure of central tendency that can be used for a categorical variable because it identifies the most frequently occurring category. The mean and median, on the other hand, require numerical data.

Question 18

Which of the following is most clearly a statement about a statistical relationship between variables?

Accepted Answer

"Pain-Away" being more effective at treating headaches than its nearest competitor is a statement about a statistical relationship between variables (the effectiveness of different headache treatments). The other options do not provide information about a relationship between variables.

Question 19

A researcher shows that doctors who act more confidently are liked better by their patients … but only up to a point. If they act too confidently, their patients start to like them less. Which of the following best describes this result?

Accepted Answer

The result shows that there is a relationship between physician confidence and patient liking, but it is not a linear relationship. The researchers have found that there is a point up to which the patients like confident doctors, but beyond that point, the patients start to like them less. This suggests a nonlinear relationship between the two variables.

Question 20

What is the median for the set of data below?

Accepted Answer

To find the median, we need to first arrange the data in numerical order:

2, 3, 6, 8, 8, 10, 52, 64

The middle number of the set is the median. Since there are an even number of items in the set, we take the average of the two middle numbers (8 and 10) to get the median, which is 8.5. Therefore, the best choice is C.

Quiz 12: Descriptive Statistics