Question

One sample of n=12 scores has a mean of M=7 and a second sample of n=8 scores has a mean of M=12. If the two samples are combined, what is the mean for the combined sample?

Answer 1

To find the mean for the combined sample, multiply each sample mean by its sample size, add the products, and divide by the total sample size.

Step-by-step explanation:

To find the mean for the combined sample, you need to calculate the weighted average of the two sample means. The weight is determined by the sample size.

First, multiply the sample mean of the first sample by its sample size, and do the same for the second sample mean and sample size.

Then, add the two products together and divide by the total sample size (n1 + n2) to get the mean for the combined sample.

In this case, the mean for the combined sample would be ((7 * 12) + (12 * 8)) / (12 + 8) = 8.25.