Visual Solutions
3 step-by-step animated solutions for Statistics. Each solution breaks the problem into visual clips with key insights.
Tricky4 steps
Two groups of 20 and 30 students have means 50 and 60, and standard deviations 4 and 5 respectively. The variance of the combined group of 50 students is:
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Hard4 steps
If the mean and variance of eight numbers 3, 7, 9, 12, 14, 20, and are 10 and 25 respectively, then is equal to:
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Hard4 steps
Let the observations () satisfy and . Then the variance of is:
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