Statistics fall review

Front

What does it mean if a distribution is skewed to the left?

Back

A distribution is skewed to the left when the left tail (lower values) is longer or fatter than the right tail, indicating that the majority of the data points are concentrated on the right side.

Front

How do you calculate the probability of losing two independent matches if the probability of winning is 0.6?

Back

The probability of losing is 1 - 0.6 = 0.4. For two independent matches, the probability of losing both is 0.4 * 0.4 = 0.16.

Front

What does a residual plot indicate about the relationship between observed and predicted values?

Back

A residual plot shows the difference between observed values and predicted values. If a point is above the horizontal line at zero, the actual value is larger than the predicted value; if below, it is smaller.

Front

What does a correlation coefficient of r = 0.89 indicate about the relationship between two variables?

Back

A correlation coefficient of r = 0.89 indicates a strong positive linear relationship, meaning that as one variable increases, the other variable tends to also increase.

Front

What is the purpose of random assignment in experiments?

Back

Random assignment is used to create roughly equivalent groups before treatments are administered, helping to eliminate bias and ensure that the results are due to the treatment rather than pre-existing differences.

Front

Define 'independent events' in probability.

Back

Independent events are two or more events where the occurrence of one event does not affect the probability of the other event occurring.

Front

What is a residual in statistics?

Back

A residual is the difference between the observed value and the predicted value of a data point in a regression analysis.

Front

Explain the concept of 'normal distribution'.

Back

A normal distribution is a bell-shaped distribution 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 significance of a p-value in hypothesis testing?

Back

A p-value indicates the probability of obtaining test results at least as extreme as the observed results, assuming that the null hypothesis is true. A low p-value suggests that the null hypothesis may be rejected.

Front

What does it mean if a data set is uniformly distributed?

Back

A uniformly distributed data set has all outcomes equally likely, meaning that each value within a certain range has the same probability of occurring.