Question 1

The null hypothesis suggests that the two samples come from ___________ distribution(s), and the experimental hypothesis suggests that the two samples come from _____________ distribution(s).

Accepted Answer

The null hypothesis typically assumes that there is no effect or difference between groups, implying that the two samples come from the same distribution. The experimental hypothesis suggests that there is an effect or difference, implying the samples come from different distributions.

Question 2

In comparison with a confidence level of 0.05, a confidence level of 0.01 means

Accepted Answer

A confidence level of 0.01 indicates a stricter criterion for rejecting the null hypothesis, meaning you need stronger evidence to be more sure that the null hypothesis is wrong compared to a confidence level of 0.05.

Question 3

The mean is

Accepted Answer

The mean is defined as the arithmetic average of a set of numbers, calculated by adding all the numbers together and then dividing by the count of those numbers.

Question 4

If the mean I.Q. score is 100 and the standard deviation of I.Q. scores is 15, then an I.Q. of 130 will have a z-score (or standard score) of

Accepted Answer

A z-score is calculated by subtracting the mean from the individual score and then dividing by the standard deviation. For an I.Q. of 130, the calculation is (130 - 100) / 15 = 30 / 15 = 2.00.

Question 5

Inferential statistics allow you to decide whether a difference between the experimental and the control group is due to _______________ or ________________.

Accepted Answer

Inferential statistics are used to determine if observed differences between groups (such as experimental and control groups) are due to the manipulation of the independent variable or simply due to chance. This allows researchers to make inferences about the population based on sample data.

Question 6

The ___________ is the standard deviation of sample means.

Accepted Answer

The standard error is the standard deviation of the sampling distribution of a statistic, most commonly of the mean.

Question 7

A conservative statistical test is one that

Accepted Answer

A conservative statistical test is designed to minimize the risk of making a Type I error, which is the incorrect rejection of a true null hypothesis. However, this conservatism often comes at the cost of increasing the likelihood of a Type II error, which is failing to reject a false null hypothesis.

Question 8

Failing to reject the null hypothesis when it is actually true is a

Accepted Answer

Failing to reject the null hypothesis when it is actually true is the correct decision in hypothesis testing, as it means the evidence was not strong enough to support the alternative hypothesis.

Question 9

The two properties about a set of measurements of a dependent variable that we are most interested in describing are

Accepted Answer

The two main properties of interest in a set of measurements of a dependent variable are central tendency and dispersion. Central tendency describes the middle or center of a data distribution (e.g., mean, median, mode), while dispersion (or variability) describes how spread out the data are (e.g., range, variance, standard deviation).

Question 10

An advantage of the median over the mean is that the median is

Accepted Answer

The median is less influenced by extreme scores or outliers, making it a more robust measure of central tendency in distributions with skewed data.

Question 11

The ________________ is the sum of all the scores divided by the number of scores.

Accepted Answer

The mean is defined as the sum of all the scores divided by the number of scores, representing the average value of a data set.

Question 12

A score that lies one standard deviation above the mean

Accepted Answer

In a normal distribution, a score that is one standard deviation above the mean has a z-score of +1.0. This is because the z-score measures how many standard deviations an element is from the mean.

Question 13

All of the following statements are true of the normal distribution EXCEPT

Accepted Answer

Nearly all the scores (about 95%) lie within two standard deviations of the mean in a normal distribution, not outside.

Question 14

The ______________ divides a distribution in half.

Accepted Answer

The median is the value that divides a distribution into two equal halves, meaning that half the scores are above the median and half are below.

Question 15

The standard deviation is

Accepted Answer

The standard deviation is defined as the square root of the variance, which measures the dispersion or spread of a set of data points around the mean.

Question 16

The generally preferred measure of central tendency is usually the

Accepted Answer

The mean is generally the preferred measure of central tendency because it takes into account all values in the dataset, providing a comprehensive average.

Question 17

Failing to reject the null hypothesis when it is actually false is a

Accepted Answer

A Type II error occurs when the null hypothesis is not rejected even though it is false. This means that the evidence was not strong enough to support the alternative hypothesis, even though the alternative hypothesis is true.

Question 18

Which of the following is the most useful descriptive statistic for measuring dispersion?

Accepted Answer

Standard deviation is the most useful descriptive statistic for measuring dispersion because it provides a measure of the average distance of each data point from the mean, allowing for a more comprehensive understanding of the spread of data.

Question 19

Rejecting the null hypothesis when it is actually false is

Accepted Answer

Rejecting the null hypothesis when it is actually false is a correct decision, as it means the test has correctly identified a real effect or difference.

Question 20

As the sample size (n) increases,

Accepted Answer

As the sample size increases, the standard error of the mean decreases, making the estimate more precise. This increase in precision and sample size leads to an increase in the power of statistical tests, which is the ability to detect an effect if there is one, thus decreasing the probability of a Type II error (failing to reject a false null hypothesis).

Quiz 17: Statistical Reasoning: An Introduction

The null hypothesis suggests that the two samples come from _ distribution(s) , and the experimental hypothesis suggests that the two samples come from ___ distribution(s) .

In comparison with a confidence level of 0.05, a confidence level of 0.01 means

The mean is

If the mean I.Q. score is 100 and the standard deviation of I.Q. scores is 15, then an I.Q. of 130 will have a z-score (or standard score) of

Inferential statistics allow you to decide whether a difference between the experimental and the control group is due to _ or __.

The ___________ is the standard deviation of sample means.

A conservative statistical test is one that

Failing to reject the null hypothesis when it is actually true is a

The two properties about a set of measurements of a dependent variable that we are most interested in describing are

An advantage of the median over the mean is that the median is

The ________________ is the sum of all the scores divided by the number of scores.

A score that lies one standard deviation above the mean

All of the following statements are true of the normal distribution EXCEPT

The ______________ divides a distribution in half.

The standard deviation is

The generally preferred measure of central tendency is usually the

Failing to reject the null hypothesis when it is actually false is a

Which of the following is the most useful descriptive statistic for measuring dispersion?

Rejecting the null hypothesis when it is actually false is

As the sample size (n) increases,

Quiz 17: Statistical Reasoning: An Introduction

The null hypothesis suggests that the two samples come from ___________ distribution(s) , and the experimental hypothesis suggests that the two samples come from _____________ distribution(s) .

In comparison with a confidence level of 0.05, a confidence level of 0.01 means

The mean is

If the mean I.Q. score is 100 and the standard deviation of I.Q. scores is 15, then an I.Q. of 130 will have a z-score (or standard score) of

Inferential statistics allow you to decide whether a difference between the experimental and the control group is due to _______________ or ________________.

The ___________ is the standard deviation of sample means.

A conservative statistical test is one that

Failing to reject the null hypothesis when it is actually true is a

The two properties about a set of measurements of a dependent variable that we are most interested in describing are

An advantage of the median over the mean is that the median is

The ________________ is the sum of all the scores divided by the number of scores.

A score that lies one standard deviation above the mean

All of the following statements are true of the normal distribution EXCEPT

The ______________ divides a distribution in half.

The standard deviation is

The generally preferred measure of central tendency is usually the

Failing to reject the null hypothesis when it is actually false is a

Which of the following is the most useful descriptive statistic for measuring dispersion?

Rejecting the null hypothesis when it is actually false is

As the sample size (n) increases,

The null hypothesis suggests that the two samples come from _ distribution(s) , and the experimental hypothesis suggests that the two samples come from ___ distribution(s) .

Inferential statistics allow you to decide whether a difference between the experimental and the control group is due to _ or __.