In order to process the main dataset, there is a certain amount of extra read-only data required. This data is known as side data. There are two categories of side data distribution techniques:
Via the job configuration: This method is only a viable option when the data size is small (in kilobytes). Exceeding this threshold may put unnecessary pressure on the memory usage of the Hadoop daemons especially. This is especially the case when a lot of jobs are running.
Via distributed cache - Hadoop has a distributed cache mechanism which is a better option than serializing side data using job configuration.
A standard distribution regards 95% of all data being within 2-standard deviations of either side. Similarly, within one standard deviation either way is 68% of all data. This creates a bell curve distribution. An abnormal distribution would be erratic and not follow such a statistical structure of representation.
Skewness is a statistical measure that indicates the degree of asymmetry of a distribution around its mean. A positive skewness means that the tail on the right side of the distribution is longer or fatter, while negative skewness indicates a longer or fatter tail on the left side. In essence, skewness helps to understand the direction and extent to which a dataset deviates from a normal distribution. It is often used in data analysis to assess the distribution characteristics and make informed decisions based on the data.
In mathematics, "skewed" refers to the asymmetry in the distribution of data. A skewed distribution can be either positively skewed, where the tail on the right side is longer or fatter, or negatively skewed, where the tail on the left side is longer or fatter. This indicates that the mean and median of the data may not align, often with the mean being pulled in the direction of the skew. Understanding skewness helps in analyzing the characteristics of the data and choosing appropriate statistical methods.
Unimodal skewed refers to a distribution that has one prominent peak (or mode) and is asymmetrical, meaning it is not evenly balanced around the peak. In a right (or positively) skewed distribution, the tail on the right side is longer or fatter, indicating that most data points are concentrated on the left. Conversely, in a left (or negatively) skewed distribution, the tail on the left side is longer, with most data points clustered on the right. This skewness affects the mean, median, and mode of the data, typically pulling the mean in the direction of the tail.
The answer depends on one side of WHAT! There is no distribution which has a greater number of values on either side of its median.
A skewness of 1.27 indicates a distribution that is positively skewed, meaning that the tail on the right side of the distribution is longer or fatter than the left side. This suggests that the majority of the data points are concentrated on the left, with some extreme values on the right, pulling the mean higher than the median. In practical terms, this might indicate the presence of outliers or a few high values significantly affecting the overall distribution.
When the majority of the data values fall to the right of the mean, the distribution is indeed said to be left skewed, or negatively skewed. In this type of distribution, the tail on the left side is longer or fatter, indicating that there are a few lower values pulling the mean down. This results in the mean being less than the median, as the median is less affected by extreme values. Overall, left skewed distributions show that most data points are higher than the average.
Skewness is a measure of the extent to which the probability distribution of a random variable lies more to one side of the mean, as opposed to it being exactly symmetrical.If μ and s are the mean and standard deviation of a random variable X, thenSkew(X) = Expected value of [(X - μ)/s]3
In a symmetric distribution, the mean, median, and mode are all equal or located at the same central point. This characteristic ensures that the distribution is balanced on either side, with half of the data points falling below the central value and half above it. Therefore, in a perfectly symmetric distribution, such as a normal distribution, these three measures of central tendency coincide.
Bell curves are used because they represent an exactly normal distribution. A normal distribution means that all of the values are centered around a single mean value, with the probability density decreasing equally on either side of the mean. This is the distribution that is most widely used in statistics because it is often found naturally (truly random data follows a normal distribution), and also because it follows from the central limit theorem.
The frequency distribution is likely to be symmetrical and bell-shaped, resembling a normal distribution. Given that the mean, median, and mode are all equal at 12,000 pounds, it suggests that the data is centered around this value with a balanced spread on either side. This indicates that the distribution has a single peak at the center, with a consistent frequency of values around the mean.
It is a probability distribution in which the probability of the random variable being in any interval on one side of the mean (expected value) is the same as for the equivalent interval on the other side of the mean.