Question 1

As the size of a representative sample increases,the ________ of that sample is most likely to decrease.

Accepted Answer

As the size of a representative sample increases, the sample becomes more representative of the population and thus the variability (standard deviation) of that sample is most likely to decrease.

Question 2

Professor Taylor arranged for people of different ages to complete a test of manual dexterity.She then compared manual dexterity across different age levels.The professor's research best illustrates a

Accepted Answer

The professor's method of comparing manual dexterity across different age levels suggests a cross-sectional study, which involves comparing individuals of different ages at the same point in time. Longitudinal studies would involve following the same individuals over a period of time to assess changes in manual dexterity, while the normal curve and standard deviation are statistical concepts not directly related to the design of this study.

Question 3

Regression toward the mean refers to the tendency for

Accepted Answer

Regression toward the mean refers to the tendency for extreme or unusual events to be followed by more average or typical events. This concept is commonly observed in sports, where athletes who have an exceptional performance are likely to have a less impressive performance in their next game, simply because their first performance was so exceptional.

Question 4

Colette received an unusually high grade of A on her first biology test and a B+ on the second,even though she studied equally for both tests.Which of the following best explains Colette's deteriorating pattern of performance?

Accepted Answer

Regression toward the mean suggests that when an individual performs unusually well or poorly on a particular occasion, their subsequent performance is likely to be closer to their average level of performance. Colette's high grade on her first test may have been due to chance or lucky guessing, so her lower grade on the second test represents her performance regressing toward the mean.

Question 5

A sample average can be used to estimate a population average with greater precision if the sample is

Accepted Answer

A larger sample size reduces sampling error and provides a better estimate of the population parameter. Skewed distribution, high variability, or memorable data does not necessarily improve the precision of the sample estimate.

Question 6

Researchers studied the effects of vitamin supplements on the health of more than 600 city residents throughout their adulthood.This research procedure best illustrated

Accepted Answer

The research procedure described in the question is a longitudinal study, which involves following a group of individuals over an extended period of time. This study tracked the health of more than 600 city residents throughout their adulthood, which is an example of a longitudinal study. The other answer options are not applicable to the description provided in the question.

Question 7

The precision with which a sample average approximates a population average increases as

Accepted Answer

A smaller amount of variability in the sample means that the sample points are closer to the population mean, resulting in a more precise estimate of the population mean. Conversely, a larger amount of variability in the sample means that the sample points are spread out and can be far from the population mean, resulting in a less precise estimate of the population mean.

Question 8

In research studies,psychologists use ________ to decide whether an observed difference between two groups is significant.

Accepted Answer

Psychologists use inferential statistics, such as t-tests or ANOVA, to determine whether the difference between two groups is significant. Scatterplots are used to visualize the relationship between two variables. Regression toward the mean is a statistical phenomenon in which extreme scores tend to move toward the group average on subsequent measurements. Illusory correlation is the perception of a relationship between two variables when none exists.

Question 9

Statistical reasoning can help us to generalize correctly from a

Accepted Answer

Statistical reasoning can help us make predictions about a larger group or population based on a smaller subset or sample. Therefore, generalizing from a sample to a population is a central concept in statistical reasoning.

Question 10

A cross-sectional study is one in which

Accepted Answer

A cross-sectional study involves testing different age groups at the same time, without following them over a period of years. This allows for a snapshot of different characteristics to be assessed at the same time. Option A describes a longitudinal study, option C describes a study with multiple measures on the same individual, and option D describes a study with multiple researchers.

Question 11

Educational differences between people from different generations partially account for the apparent age-related decline in mental ability found in

Accepted Answer

Cross-sectional studies compare people of different ages at the same time, but do not follow individuals over time. Therefore, they do not account for the effects of learning and educational experiences that may be different for people of different generations. As a result, educational differences between generations can contribute to the apparent age-related decline in mental ability found in cross-sectional studies.

Question 12

Unusual ESP subjects who defy chance when first tested nearly always lose the supposed "psychic powers" when retested.Parapsychologists have called this

Accepted Answer

The decline effect refers to the phenomenon where initially high scores on an ESP test are followed by a decline in performance upon retesting, suggesting that the performance was due to chance or other external factors rather than any actual psychic ability. The other options do not accurately describe this phenomenon.

Question 13

A longitudinal study is one in which

Accepted Answer

In a longitudinal study, the same group of people is tested and retested over a lengthy period. This allows researchers to observe changes and developments in the individuals over time. Choice A refers to a cross-sectional study, where different characteristics of different individuals are assessed at the same time. Choice B refers to a study comparing individuals of different ages, but it may not necessarily be longitudinal. Choice C is not a defining characteristic of a longitudinal study.

Question 14

Longer survival rates of the healthiest and most intelligent people partially account for the apparent stability of intelligence across the life span found in

Accepted Answer

Longitudinal studies track the same group of individuals over time, allowing researchers to observe changes in intelligence within that group and control for factors such as mortality rates among different groups. The longer survival rates of healthier and more intelligent individuals can lead to more stable intelligence scores in longitudinal studies, thus partially accounting for the apparent stability of intelligence across the life span. Cross-sectional studies, on the other hand, compare different age groups at the same point in time and do not control for individual differences in mortality rates. The normal curve and standard deviations are statistical concepts related to the distribution of intelligence scores, but do not directly address the issue of stability across the life span.

Question 15

In a single day,45 babies were born in hospital X,65 babies in hospital Y,and 25 babies in hospital Z.At which hospital is there the greatest probability that more than 60 percent of the babies are of the same sex?

Accepted Answer

The answer of In a single day,45 babies were born...

Question 16

Which of the following events is the most probable?

Accepted Answer

The answer of Which of the following events is the...

Question 17

To find whether observed differences between samples reflect actual differences between populations,you should determine the ________ of the observed differences.

Accepted Answer

Statistical significance is used to determine whether observed differences between samples are likely to be due to chance or actual differences between populations. The mean, median, and standard deviation describe the characteristics of a sample but do not indicate whether the differences observed between samples are statistically significant.

Question 18

Differences between two sample averages are most likely to be statistically significant if

Accepted Answer

The larger the difference between the sample averages, the more likely it is that this difference is statistically significant. This is because the larger the difference, the more unlikely it is that this difference is due to chance. Therefore, option A is the best choice. The standard deviations of the samples and whether the samples are drawn from the same population do not necessarily affect the significance of the difference between the sample averages. The sample means and medians are not relevant in this context.

Question 19

After sports magazines give cover-story attention to the recent outstanding performances of an athlete,the individual often suffers a real decline in performance.This may be at least partially explained in terms of

Accepted Answer

Regression toward the mean is the tendency for extreme scores or performance to move back towards the average. Therefore, when an athlete receives a lot of media attention for an outstanding performance, it's likely that their next performance will not be as excellent, but will instead be closer to their usual level of performance. This phenomenon is not due to illusory correlation, the illusion control, or the placebo effect.

Question 20

Cross-sectional research indicated that with age,mental ability ________.Longitudinal research indicated that as adults age,intelligence________.

Accepted Answer

Cross-sectional research often shows a decline in mental ability with age due to cohort effects, while longitudinal research suggests that intelligence remains more stable over time as it tracks the same individuals.

Quiz 15: Statistical Reasoning in Everyday Life