Question

A teacher wants to compare scores on a geology exam for two classes. The difference between the sample means is 21.4. If the standard deviation of the distribution of the difference between sample means is 16.66, and she is testing the hypothesis at the 68% confidence level, which statement is true?

The difference between the two means is significant, so the null hypothesis must be accepted.

The difference between the two means is not significant, so the alternative hypothesis must be rejected.

The difference between the two means is not significant, so the null hypothesis

Answer 1

@Rosabearof10

Answer 2

a i think

Answer 3

thx

Answer 4

The mean height of a sample of 15-year-old boys is 175 centimeters, with a standard deviation of 10. For a sample of 15-year-old girls, the mean is 165 centimeters with a standard deviation of 8.

If 8 boys and 8 girls were sampled, the standard deviation of the difference is . (Round your answer to the nearest hundredth.)