The variance measures how spread out the data is from the mean. It quantifies the average squared deviation of each data point from the mean.
Think of a group of friends going to a party. The variance would represent how spread out they are in terms of distance from each other. If they are all close together, the variance would be low, but if they are scattered far apart, the variance would be high.
Standard Deviation: The standard deviation is another measure of how spread out the data is from the mean, but it is expressed in the same units as the original data.
Mean: The mean is simply the average value of a set of numbers.
Normal Distribution: A normal distribution is a bell-shaped curve that represents a set of continuous random variables with specific characteristics.
How do you calculate the variance for a sample distribution that is for differences between two sample proportions?
If X and Y are two independent random variables, and Z = X - Y, what is the variance of Z?
If X has a mean of 15 and a variance of 4, and Y has a mean of 8 and a variance of 2, what is the variance of X - Y?
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