RA Statistical Analysis and Interpretation

Question 1

In hypothesis testing, a p-value of 0.03 indicates which of the following?

Accepted Answer

There is a 3% chance of observing the results if the null hypothesis is true

Answer

The p-value represents the probability of obtaining the observed results (or more extreme) assuming the null hypothesis is true, not the probability that the null hypothesis itself is true.

Question 2

Which measure of central tendency is MOST affected by extreme outliers in a dataset?

Accepted Answer

Mean

Answer

The mean incorporates every data value in its calculation, so a single extreme outlier can substantially shift it, unlike the median or mode which are more resistant to outliers.

Question 3

What is the primary distinction between descriptive and inferential statistics?

Accepted Answer

Descriptive statistics summarize a sample; inferential statistics draw conclusions about a population

Answer

Descriptive statistics organize and summarize data from a collected sample, while inferential statistics use that sample data to make generalizations or predictions about a broader population.

Question 4

A 95% confidence interval for a mean of 50 is (46, 54). How should this be correctly interpreted?

Accepted Answer

If the study were repeated many times, 95% of such intervals would contain the true population mean

Answer

A confidence interval is a frequentist concept meaning that if the procedure were repeated many times, 95% of the constructed intervals would contain the true parameter value.

Question 5

Which statistical test is most appropriate to compare the means of two independent groups when the data is normally distributed?

Accepted Answer

Independent samples t-test

Answer

The independent samples t-test is designed specifically to compare the means of two separate, unrelated groups when the assumption of normality is met.

RA - Certified Research Assistant Practice Test

RA - Certified Research Assistant Practice Test

RA Statistical Analysis and Interpretation