The dot plots below show students' typing speed at the beginning and end of a typing course. SELECT ALL the statements that are true about the dot plots below... 1. Overall, the students improved by the end of the course.

2. There are 20 students enrolled in the course.

3. The center of the data is 20 words per minute for both dot plots.

4. The center of the end of course dot plot is about 27 wpm.

5. The range of beginning of course data is 20 wpm.

Aresearch study is studying the effects of a new drug for osteoporosis alzheimer's disease (ad) for women above the age of 65 years. a group of individuals with osteoporosis is randomized into two groups. one group is treated conventionally, and the second group is treated with the new medication. assessments are made at 3, 6, 12, 36, and 48 months. the conventionally treated group is assessed for ad using a serum blood test, and the treatment group is assessed for ad using a pet radiotracer that binds to beta-amyloid plaques. in comparing these 2 trial arms, the authors of the study may encounter which type of bias? a. selection bias on the risk of developing b. measurement bias c. confounding bias d. recall bias e. lead-time bias