What do you call the data value that is extremely large or small compared to the other values among the data set?

The mode of a data set is the value that occurs most often. A data set can have no mode, one mode, or more than one mode. The range of a data set is the difference between the largest and smallest values in the set.

What measures can have more than one value for a set of data?

The median and mean can only have one value for a given data set. The mode can have more than one value (see Mode section on previous page).

What is measure of variability?

Four measures of variability are the range (the difference between the larges and smallest observations), the interquartile range (the difference between the 75th and 25th percentiles) the variance and the standard deviation.

When can mean be misleading?

The mean treatment outcome (or average) is often reported in comparing the results of different groups in a clinical trial. However, sometimes the average result can be misleading. The mean may be misleading because of uneven spread in the results or uncertainty about whether patients had an important improvement.

How many data values are in the set?

There are 8 values in the data set. The fourth and fifth scores, 16 and 17, are in the middle. That is, there is no one middle value.

When a data set has a single mode it is known to have what type of distribution?

A unimodal distribution has one mode. A single peak can take on many shapes (e.g. very tall and thin or very squat and fat). One of the most common types of unimodal distributions is the normal distribution, sometimes called the “bell curve” because its shape looks like a bell.

What happens when you have 2 modes?

If there are two numbers that appear most often (and the same number of times) then the data has two modes. This is called bimodal. If all the numbers appear the same number of times, then the data set has no modes.

Can a data set have more than one mode?

Examples of the Mode A set of numbers can have more than one mode (this is known as bimodal if there are two modes) if there are multiple numbers that occur with equal frequency, and more times than the others in the set.

What does high variability mean?

Variability refers to how spread out a group of data is. In other words, variability measures how much your scores differ from each other. Data sets with similar values are said to have little variability, while data sets that have values that are spread out have high variability.

What does it mean to say that one data set or distribution has more variability than another?

When a distribution has lower variability, the values in a dataset are more consistent. However, when the variability is higher, the data points are more dissimilar and extreme values become more likely.

How can an average be misinterpreted?

It is statistical err to apply the average of a group of data points to a single point and assume it to be true. Averages are misleading when used to compare different groups, apply group behavior to an individual scenario, or when there are numerous outliers in the data.

How statistics can be misleading?

The data can be misleading due to the sampling method used to obtain data. For instance, the size and the type of sample used in any statistics play a significant role — many polls and questionnaires target certain audiences that provide specific answers, resulting in small and biased sample sizes.

How many middle values are there in the data set?

There are 8 values in the data set. The fourth and fifth scores, 16 and 17, are in the middle. That is, there is no one middle value. Note: Half of the values in the data set lie below the median and half lie above the median.

What are the appropriate measures of variability in data?

For data measured at an ordinal level, the range and interquartile range are the only appropriate measures of variability.

How do we use statistics to obtain information about a population?

We use statisticssuch as the mean, medianand modeto obtain information about a populationfrom our sampleset of observed values. Mean The mean (or average) of a set of data values is the sumof all of the data values divided by the number of data values. That is:

What is the best measure to use for normal distribution?

For normal distributions, all measures can be used. The standard deviation and variance are preferred because they take your whole data set into account, but this also means that they are easily influenced by outliers. For skewed distributions or data sets with outliers, the interquartile range is the best measure.