# Statistics Description

### Description

Question Displays the question name.
Sample Size Displays the valid number of respondents who answered the specific question.
Missing Displays the number of responses that are missing (blank).
Mean The average of the values in the population.
Variance A measure of how spread out a distribution is. It is computed as the average squared deviation of each number from its mean.
Standard Deviation A Measure of the dispersion of a set of data from its mean. The more spread apart the data is, the higher the deviation. It is calculated by taking the square root of the variance.
Standard Error The standard deviation of the sampling distribution of that statistic. Standard error reflect how much sampling fluctuation a statistic will show.
Minimum The minimum value in a range.
Maximum The maximum value in a range.
Range The distance between the maximum and minimum value.
Skewness A measure of the symmetry or lack of it in a set of data as evident from the shape of the distribution. A distribution is symmetric if the left half of the graph of the distribution is the mirror image of the right half. If a distribution is skewed to the right (positive skewness) the mean is greater than zero. If a distribution is skewed to the left (negative skewness) then the relationship is reversed; in which case the coefficient is less than zero. If there is no skewness or the distribution is symmetric like the bell-shaped normal curve then the mean=median=mode.
Kurtosis Kurtosis is based on the size of a distributions’s tails. Distributions with relatively larfe tails are called “leptokurtic”; those with small tails are called “platykurtic”. A distribution with the same kurtosis as the normal distribution is called “mesokurtic”.
T-Value A measure on a random sample (or pair of samples) in which a mean (or pair of means) appears in the numerator and an estimate of the numerator’s standard deviation appears in the denominator. The latter estimate is based on the calculated s square or s squares of the samples. If these calculations yield a balue of (t) that is sufficiently different from zero, the test is considered to be statiscally significant.
Mean Absolute Vebiation A measure of variation, which calculates the average distance a data balue is from the mean.
Percentile (25 and 75) Percentiles are values that divide a sample of data into one hundred groups containing (as far as possible) equal numbers of observations. For example, 25% of the data values lie below the 25th percentile.
Median The middle of a distribution: half the values are above the median and half are below the median.
Inter Quartile Range The difference between the 75th percentile and the 25th percentile.
Confidence Interval
(1, 5, 95, and 99%)
A confidence interval gives an estimated range of values that is likely to include an unknown population parameter, the estimated range being calculated from a given set of sample data. If independent samples are taken repeatedly from the same population, and a confidence interval calculated for each sample, then a certain percentage (confidence level) of the intervals will include the unknown population parameters. Remark Quick Stats calculates Confidence Intervals of 1%, 5%, 95%, and 99%.