A researcher wants to compare the effects of four dosages of a new medication on memory. A sample ofn= 25 people is gathered. Their memory is first measured with 0mg of the medication. Later, the sample is given a 5mg dose, and their memory is again tested. Then, the sample is given a 10 mg dose, and retested. Finally, the sample is given a 20 mg dose, and their memory is tested one last time. The correct hypothesis test for this design would be a(n)