Q: Which of the following is a correct interpretation of a statistically significant result at $p < 0.05$?

There is less than a $5\%$ probability that the observed result would occur if the null hypothesis were true.

Question 1

Which of the following best describes the main difference between descriptive and inferential statistics in psychological research?

Accepted Answer

Descriptive statistics summarize basic features of data from a sample, while inferential statistics allow researchers to make conclusions about the meaning of the data.

Question 2

A researcher wants to test whether playing video games leads to aggressive behavior. Which of the following is the correct identification of the independent and dependent variables in this experiment?

Accepted Answer

Independent variable: Playing video games; Dependent variable: Aggressive behavior

Question 3

Which of the following is a requirement for establishing causality in an experimental design?

Accepted Answer

Random assignment to groups and a control condition as similar as possible to the experimental condition

Question 4

A psychologist is interested in whether childhood self-control predicts financial well-being in adulthood. She follows the same group of participants for 20 years, measuring self-control at age 8 and financial status at age 28. What research method is she using?

Accepted Answer

Longitudinal method

Question 5

Which of the following best defines internal validity in psychological research?

Accepted Answer

The degree to which changes in the dependent variable are really due to the independent variable

Question 6

A study finds a Pearson's $r$ of $0.55$ between hours spent studying and exam scores. According to Cohen's conventions, how would you interpret the strength of this relationship?

Accepted Answer

Large

Question 7

In a normal distribution, what percentage of scores falls within two standard deviations of the mean according to the 68-95-99.7 rule?

Accepted Answer

$95\%$

Question 8

A researcher conducts a $t$-test comparing the means of two groups and obtains a $p$-value of $0.03$. What does this $p$-value indicate?

Accepted Answer

Assuming the null hypothesis is true, there is a $3\%$ probability of obtaining a result as extreme or more extreme than the observed result.

Question 9

Which of the following is a potential weakness of longitudinal methods in psychological research?

Accepted Answer

Attrition (participants dropping out over time)

Question 10

A psychologist wants to know if there is a relationship between stress and health over time. She measures both variables in the same group of people every year for 10 years. What type of correlation is she most likely to use to analyze the relationship between these two variables?

Accepted Answer

Pearson's $r$

Question 11

Which of the following scenarios best illustrates the concept of external validity?

Accepted Answer

A study's findings can be generalized to real-world settings outside the laboratory.

Question 12

Which of the following is NOT a requirement for a true experiment?

Accepted Answer

Measurement of variables at multiple time points

Question 13

A researcher finds that the mean score on a memory test is $75$, with a standard deviation of $5$. What is the $z$-score for a participant who scored $85$?

Accepted Answer

$z = 2$

Question 14

Which of the following best describes the purpose of a double-blind procedure in experimental research?

Accepted Answer

To ensure that neither the participants nor the experimenters know which group participants are in, reducing bias.

Question 15

If a distribution of test scores has a mean of $100$ and a standard deviation of $15$, what range of scores would include approximately $68\%$ of the data?

Accepted Answer

$85$ to $115$

Question 16

Which of the following is a correct interpretation of a statistically significant result at $p < 0.05$?

Accepted Answer

There is less than a $5\%$ probability that the observed result would occur if the null hypothesis were true.

Question 17

A researcher is interested in whether students remember information better if they cram or space out their studying. Which of the following best describes the independent and dependent variables in this experiment?

Accepted Answer

Independent variable: Type of studying (cramming vs. spacing); Dependent variable: Memory performance

Question 18

Which of the following is a strength of experimental methods in psychological research?

Accepted Answer

Ability to establish causality

Question 19

A study finds a negative correlation between hours of TV watched per week and GPA among college students. Which of the following is a correct interpretation of this finding?

Accepted Answer

As hours of TV watched increase, GPA tends to decrease.

Question 20

Which of the following best describes the 68-95-99.7 rule in a normal distribution?

Accepted Answer

$68\%$ of scores fall within $1$ standard deviation, $95\%$ within $2$, and $99.7\%$ within $3$ standard deviations of the mean.

Research Methods and Statistics in Introductory Psychology

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