Advantages of using a related sample (either one sample of participants with repeated measures or two matched samples) versus using two independent samples include which of the following? Check all that apply.

1. Related samples (specifically, one sample of participants with repeated measures) can have a carryover effect such that participants can learn from their first measurement and therefore do better on their second measurement.
2. A study that uses related samples to compare two drugs (specifically, one sample of participants with repeated measures) can have a carryover and/or order effect such that the effects of the drug taken before the first measurement may not wear off before the second measurement.
3. A related-samples design reduces or eliminates problems caused by individuals differences such as age, IQ, gender, or personality.
4. Related samples (specifically, one sample of participants with repeated measures) require fewer participants for the same degree of power.