Statistics: Lessons 1-5

Front

What is the mean in statistics?

Back

The mean is the average of a set of numbers, calculated by adding all the values together and dividing by the number of values.

Front

What is standard deviation?

Back

Standard deviation is a measure of the amount of variation or dispersion in a set of values. A low standard deviation means that the values tend to be close to the mean, while a high standard deviation indicates that the values are spread out over a wider range.

Front

What does it mean if data is normally distributed?

Back

If data is normally distributed, it means that the data follows a bell-shaped curve, where most of the observations cluster around the central peak and probabilities for values further away from the mean taper off equally in both directions.

Front

What is the empirical rule in statistics?

Back

The empirical rule states that for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, about 95% falls within two standard deviations, and about 99.7% falls within three standard deviations.

Front

What is the interquartile range (IQR)?

Back

The interquartile range (IQR) is a measure of statistical dispersion, calculated as the difference between the first quartile (Q1) and the third quartile (Q3). It represents the range within which the central 50% of the data lies.

Front

What does skewed right mean in a data distribution?

Back

A right-skewed distribution has a longer tail on the right side, indicating that there are a few high values that are pulling the mean to the right of the median.

Front

How do you calculate the z-score?

Back

The z-score is calculated by subtracting the mean from the value and then dividing by the standard deviation: z = (X - μ) / σ.

Front

What is a percentile in statistics?

Back

A percentile is a measure used to indicate the value below which a given percentage of observations in a group of observations falls.

Front

What is the difference between population and sample in statistics?

Back

A population includes all members of a specified group, while a sample is a subset of the population used to represent the group.

Front

What is a confidence interval?

Back

A confidence interval is a range of values, derived from a data set, that is likely to contain the value of an unknown population parameter.