Data Analysis Comprehensive Review

Front

What happens to the standard deviation when an outlier is added to a data set?

Back

The standard deviation will increase because the outlier increases the spread of the data.

Front

What does a right-skewed box plot indicate about the data distribution?

Back

A right-skewed box plot indicates that the majority of the data points are concentrated on the left side, with a tail extending to the right.

Front

What is the definition of a sampling method that fairly represents a population?

Back

A sampling method that fairly represents a population ensures that every individual has an equal chance of being selected, minimizing bias.

Front

How do you calculate the standard deviation of a data set?

Back

To calculate the standard deviation, find the mean of the data, subtract the mean from each data point, square the results, find the average of those squared differences, and then take the square root.

Front

What is the formula for sample variance?

Back

The formula for sample variance is: s² = Σ(xi - x̄)² / (n - 1), where xi represents each data point, x̄ is the sample mean, and n is the number of data points.

Front

What is the difference between population variance and sample variance?

Back

Population variance uses N (the total number of data points) in the denominator, while sample variance uses (n - 1) to account for sample size.

Front

What does it mean if a data set has a low standard deviation?

Back

A low standard deviation means that the data points are close to the mean, indicating less variability.

Front

What is the significance of the interquartile range (IQR) in data analysis?

Back

The interquartile range (IQR) measures the middle 50% of the data, providing a measure of variability that is resistant to outliers.

Front

How can you identify outliers in a data set?

Back

Outliers can be identified using the IQR method: any data point that lies below Q1 - 1.5*IQR or above Q3 + 1.5*IQR is considered an outlier.

Front

What is the purpose of a box plot in data analysis?

Back

A box plot visually summarizes the distribution of a data set, showing the median, quartiles, and potential outliers.