Question 1

A Type II error is defined as:

Accepted Answer

A Type II error occurs when a researcher fails to find a significant effect that does, in fact, exist. This is also referred to as a false negative, as the researcher incorrectly concludes that there is no effect when one truly exists.

Question 2

In the distribution 1, 1, 1, 10, 20, 28, 30, the mode is 1.

Accepted Answer

The mode in this distribution is 1, which means it is the value that appears most frequently. This makes statement A true.

Question 3

A frequency distribution is a summary of how often various scores occur in a sample of scores.

Accepted Answer

A frequency distribution is a graphical representation or a table showing the frequency of different data values or intervals of a sample.

Question 4

In analyzing the results of his study, Dr. Cohen's statistical calculations showed there was less than 1 chance in 100 that his findings were due to random factors alone. Dr. Cohen canbe fairly confident his results are:

Accepted Answer

When the statistical calculations show that there is less than 1 chance in 100 that the findings were due to random factors alone, it indicates that the results are statistically significant. This means that the findings are not likely to have occurred by chance and have practical or theoretical importance.

Question 5

A _____ is a representative subset of _____.

Accepted Answer

A sample is a smaller group that is selected to represent a larger population, so a sample is a representative subset of the population. The other answer choices are incorrect because they either confuse different statistical concepts or do not accurately describe the relationship between a sample and a population.

Question 6

An a symmetrical distribution of scores is called a skewed distribution.

Accepted Answer

A skewed distribution is one where the scores are not evenly distributed around the mean, resulting in a lack of symmetry.

Question 7

A measure of central tendency is a single number that presents information about the spread of scores or variability in afrequency distribution.

Accepted Answer

A measure of central tendency represents the center or typical value of a dataset, not the spread or variability. Measures of variability, such as range, variance, and standard deviation, describe the spread.

Question 8

The Merchant Marketing Company wanted to target 18- to25-year-old males for a new product, so they selected a random, representative subset of this group for test marketing. In this example, the target group is the _____ andthe random, representative subset of the group is the _____.

Accepted Answer

The target group is the population, which is the entire group of 18- to 25-year-old males. The random, representative subset of this group is the sample, which was selected for test marketing. Therefore, option A is the correct choice.

Question 9

In a positively skewed distribution, most people have high scores.

Accepted Answer

In a positively skewed distribution, most people have low scores, with a few high scores pulling the tail to the right.

Question 10

A symmetrical distribution is one in which the scores fall equally on both sides of the graph.

Accepted Answer

A symmetrical distribution is also known as a normal distribution or a bell-shaped curve, where the mean, median, and mode are all the same value and fall in the center of the distribution. Scores are evenly distributed on both sides of the mean, creating a symmetrical appearance.

Question 11

A histogram is a way of graphing a frequency distribution,where frequency is marked above each score category on the graph's horizontal axis and the marks are connected by straight lines.

Accepted Answer

A histogram uses bars to represent the frequency of data within certain intervals, not connected lines. The bars touch each other to indicate continuous data.

Question 12

One way to minimize or avoid the probability of a Type II error occurring is to:

Accepted Answer

Increasing the power of the study by improving the design and increasing the number of subjects or participants can help improve the accuracy of the study and reduce the risk of Type II error. This is because a larger sample size and a better experimental design can increase the likelihood of detecting a true effect or difference between groups, reducing the probability of accepting a false null hypothesis. Options B, C, and D do not specifically address the issue of Type II error and may not necessarily reduce the risk of this type of error.

Question 13

After a study showed a significant effect, the researchers believed it would be best to repeat or replicate the study so asto have greater confidence that the effect was real and reliable.They are doing this in order to guard against the possibility that:

Accepted Answer

Replicating or repeating a study is done in order to guard against the possibility that a Type I error occurred in the original study. This means that the effect found in the original study may have been due to chance or some other factor, and not actually a real effect. By replicating the study, researchers can ensure that the effect is real and reliable. A Type II error would occur if the original study failed to find a real effect that actually exists, and this is not a concern in this situation. The power of the original study is also not a concern, as the decision to replicate the study is based on the significant effect that was found, indicating that the study had sufficient power to find the effect. The idea of a spurious effect due to too much power is also not relevant in this situation.

Question 14

Descriptive statistics are used to organize, summarize, and interpret data.

Accepted Answer

Descriptive statistics are specifically designed to provide an overview of data through measures such as mean, median, mode, range, variance, and standard deviation. They help to describe and summarize attributes of a dataset, making it easier to interpret and understand the data.

Question 15

In a negatively skewed distribution, most people have low scores.

Accepted Answer

In a negatively skewed distribution, most scores are high, with the tail extending towards the lower end.

Question 16

A measure of central tendency is a single number that presents some information about the "center" of a frequency distribution.

Accepted Answer

A measure of central tendency is indeed a single number that summarizes the "center" of a frequency distribution. Common measures of central tendency include the mean, median, and mode.

Question 17

The results of Dr. Koopman's study failed to reach statistical significance, so he replicated the study using a better research design and twice as many participants. He has _____ to avoid the possibility of a Type II error.

Accepted Answer

By increasing the number of participants and using a better research design, Dr. Koopman has increased the power of his study, which reduces the risk of a Type II error (failing to reject a false null hypothesis). Simply increasing the level of statistical significance (B) would not necessarily address the root cause of the lack of significance in the original study. Decreasing the power of the study (C) or skewing the data (D) would not be appropriate actions to address a lack of statistical significance.

Question 18

The mode is the sum of a set of scores in a distribution divided by the number of scores, and it is usually the most representative measure of central tendency.

Accepted Answer

The mode is the value that occurs most frequently in a distribution. The statement describes the calculation for the mean.

Question 19

A frequency polygon is a type of bar chart using vertical bars that touch.

Accepted Answer

A frequency polygon is a type of line graph that represents the distribution of data by connecting points with straight lines. It is not a bar chart using vertical bars that touch.

Question 20

The mean is the most frequently occurring score in a distribution.

Accepted Answer

The statement is false. The mean is the average score in a distribution, calculated by summing all the scores and dividing by the total number of scores. The most frequently occurring score is the mode.

Quiz 13: Psychological Disorders