Question

1 In a research report from an experiment, the term a statistically significant difference is used to indicate ____________ .

• A. that the there is a very low probability (i.e., 5% or less) the difference obtained in the study could happen by chance
• B. that the there is a high probability (i.e., 95% or more) the difference obtained in the study could happen by chance
• C. that the difference is large
• D. b & c

2 determining a person’s height would involve measurement on a(n) __________ scale.

• A. ratio
• B. interval
• C. ordinal
• D. nominal

3 A research report describing the results of a repeated-measures study states, "The data showed a significant difference between treatments, t(22) = 4.91, p < 0.05” From this report you can conclude that the outcome of the hypothesis test was ______________.

• A. to reject the null hypothesis and that indicates that the treatment had no effect.
• B. It is impossible to determine whether or not the null hypothesis was rejected from the information given.
• C. to fail to reject the null hypothesis and that indicates that the treatment had no effect.
• D. to fail to reject the null hypothesis and that indicates that the treatment did produce a significant effect on participants ‘behavior.
• E. to reject the null hypothesis and that indicates that the treatment did produce a significant effect on participants’ behavior.

4 If the researchers of the experiment described in question 11 committed Type I error in hypothesis testing that would mean ______. .

• A. they falsely concluded that having breakfast has a significant effect on math test scores.
• B. they correctly concluded that having breakfast has a significant effect on math test scores.
• C. they falsely concluded that having breakfast has no effect on math test scores.
• D. None of the above.

5 If the researchers of the experiment described in question 11 committed Type I error in hypothesis testing that would mean ______. .

• A. they falsely concluded that having breakfast has a significant effect on math test scores.
• B. they correctly concluded that having breakfast has a significant effect on math test scores.
• C. they falsely concluded that having breakfast has no effect on math test scores.
• D. None of the above.

6 A sample has the mean of M = 50 and the standard deviation of s = 9. If you randomly select a single score from this sample, on the average, how close would it be to the sample mean? (Hint: what is measured by standard deviation?)

• A. Within 9 points above or below the mean.
• B. Within 5 points above or below the mean.

• C. Within 3 points above or below the mean.

• D. Can’t determine from the information given.

Answer 1

Answers: 1) Option A is correct. In a research report from an experiment, the term a statistically significant difference is used to indicate-- that the there is a very low probability (i.e., 5% or less) the difference obtained in the study could happen by chance. Since a data set is typically deemed to be statistically significant if the probability of the phenomenon being random is less than 1/20, resulting in a p-value of 5%.

2) Option A is correct --determining a person’s height would involve measurement on a ratio scale. Physical characteristics of persons and objects can be measured with ratio scales, and, thus, height is an example of ratio measurement. A score of 0 means there is a complete absence of height.

3) Option E is correct, i.e., From this report, we can conclude that the outcome of the hypothesis test was to reject the null hypothesis and that indicates that the treatment did produce a significant effect on participants’ behavior. When the test result exceeds the p-value, the null hypothesis is accepted. When the test result is less than the p-value, the null hypothesis is rejected. Here p-value is less than 0.05 (given).

4) Option A is correct, i.e., if the researchers of the experiment described in question 11 committed Type I error in hypothesis testing that would mean they falsely concluded that having breakfast has a significant effect on math test scores. Since Type 1 error means rejecting the null hypothesis when it is true. The null hypothesis here has been to check that breakfast and math scores are not significantly related to each other, it is falsely rejected when it was true.

5) Same as 4

6) Option A is correct. A sample has the mean of M = 50 and the standard deviation of s = 9. If we randomly select a single score from this sample, on the average, it would be within 9 points above or below the mean.