Research Methods 2

What is a histogram?

• reports how many times a group of values appears in a dataset

What is a frequency distribution? What does a normal distribution look like+ alternative name?

A smooth curve drawn by connecting the peaks of each bar in a histogram

Gaussian distribution: bell-shaped curve with a peak at the mean

Three measures of central tendency?

mean, median, mode

Why can’t we rely on descriptive statistics alone?

• even two identically treated groups will have variability in their descriptive statistics by random chance

What are inferential statistics?

statistics that allow us apply data from sample results to larger populations

What is a t-test and what does it produce?

• a test that determines the probability that both samples come from the same population

• produces a p-value: value between 0 and 1 indicating the likelihood that difference in data occurs by random chance

What p-value makes results statistically signfiicant?

If p < .05 → results are statistically significant

what does a p-value of 0.44 mean?

assuming the treatment has no effect, there is a 44% chance of seeing a difference like this due to random sampling

what is the correlation coefficient?

r