A researcher is interested in whether blind Braille readers could be taught to read faster using the same techniques as sighted readers. He has blind adults complete a reading speed test before and after a six-week speed-reading course. In the beginning of the study, a randomly selected group of 121 blind Braille readers scored an average of 261 words per minute on the reading speed test. Since the sample size is larger than 30, the researcher can assume that the sampling distribution of MD is normal. He plans to use a repeated-measures t test. The researcher identifies the null and alternative hypotheses as:
