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What to do if there are 2 medians?

But if there is an even number of data points, then there are two numbers in the middle. In that case, you have to add those two numbers together and then divide by two to find the median. The mode of a data set refers to the number that occurs most often.

What is the median of two numbers?

The median of a set of numbers is the middle number in the set (after the numbers have been arranged from least to greatest) — or, if there are an even number of data, the median is the average of the middle two numbers.

What is a unique mode?

The mode of a set of observations is the most commonly occurring value. For example, for a data set (3, 7, 3, 9, 9, 3, 5, 1, 8, 5) (left histogram), the unique mode is 3. A distribution with more than one mode is said to be bimodal, trimodal, etc., or in general, multimodal.

What does little C mean in statistics?

So the probability = 16. The probability of an event is shown using “P”: P(A) means “Probability of Event A” The complement is shown by a little mark after the letter such as A’ (or sometimes Ac or A): P(A’) means “Probability of the complement of Event A”

How do you find C in statistics?

The c-statistic is equal to the AUC (area under the curve), and can also be calculated by taking all possible pairs of individuals consisting of one individual who experienced a positive outcome and one individual who experienced a negative outcome.

What is the formula for sample?

= ( Σ xi ) / n. All that formula is saying is add up all of the numbers in your data set ( Σ means “add up” and xi means “all the numbers in the data set). This article tells you how to find the sample mean by hand (this is also one of the AP Statistics formulas).

What is considered a good C statistic?

Glossary Definition Models are typically considered reasonable when the C-statistic is higher than 0.7 and strong when C exceeds 0.8 (Hosmer & Lemeshow, 2000; Hosmer & Lemeshow, 1989).

What does a higher C statistic mean?

The C statistic is interpreted as the probabil- ity that a randomly selected subject who experienced the outcome will have a higher predicted probability of having the outcome occur than a randomly selected subject who did not experience the outcome.

Is AUC same as C statistic?

Harrel’s concordance index C is defined as the proportion of observations that the model can order correctly in terms of survival times. When censoring is observed the statistic only includes those patient pairs for which valid comparisons can be made. Sometimes C is called the AUC.

Is C statistic same as Auroc?

C statistic is illustrated as an ROC curve, this can be used for rank order statistic; for example, to interpret a pair of patients with and without the outcome.

What is a good concordance index?

There are 7 concordant pairs out of 8 possible pairs so the concordance index is equal to 7/8 or 0.875. Concordance indexes of random predictions. Random predictions give a mean concordance index of approximately 0.5. So basically a model that hasn’t learned anything give a mean concordance index of 0.5.

What is sensitivity in ROC curve?

In a ROC curve the true positive rate (Sensitivity) is plotted in function of the false positive rate (100-Specificity) for different cut-off points of a parameter. Each point on the ROC curve represents a sensitivity/specificity pair corresponding to a particular decision threshold.