A middle school wanted to evaluate the efficacy of a 6-month…

A middle school wanted to evaluate the efficacy of a 6-month after-school program designed to teach 7th grade students math concepts. The program involved weekly sessions that used computer apps that had tutorials and practice problems. Students (n= 100) who were struggling in math (based on 6th grade math scores) were included in the program.  At the beginning of the year the students took a math pretest (reliability = .45) and scored a mean of 15 (out of 100). After 6-months 65 of the 100 students remained in the program.  These 65 students were posttested and scored an average of 45 on the identical test that was used at pretest (out of 100).  The reliability of the posttest was .75. For each threat to internal validity, define the threat and briefly discuss if this threat is likely. Statistical regression

A researcher was interested in comparing the effectiveness o…

A researcher was interested in comparing the effectiveness of 3 types of instructional materials for teaching 1 biology concept. The instructional materials included: using text materials, video materials, text + video materials.  25 10th grade Biology students were randomly assigned to each type of instructional material for a total of 75 students.  These 75 students were volunteers  recruited from an after-school program.  Students used the method for 1, 2-hour session and were then tested using a 20 item Biology exam. What is the dependent variable(s)?

A researcher was interested in comparing the effectiveness o…

A researcher was interested in comparing the effectiveness of 3 types of instructional materials for teaching 1 biology concept. The instructional materials included: using text materials, video materials, text + video materials.  25 10th grade Biology students were randomly assigned to each type of instructional material for a total of 75 students.  These 75 students were volunteers  recruited from an after-school program.  Students used the method for 1, 2-hour session and were then tested using a 20 item Biology exam. The researcher used random assignment. List 1 other method the researcher could use to control and reduce extraneous and confounding variables?

A box contains 79 coins, only dimes and quarters.  The amoun…

A box contains 79 coins, only dimes and quarters.  The amount of money in the box is $12.70.   How many quarters and dimes are in the box? TYPE YOUR WORK IN THE BOX BELOW.     NO WORK = NO POINTS                   NO CREDIT FOR GUESS & CHECK a.  Clearly assign an algebraic expression to each coin (use only ) b.  Write an algebraic equation modeling the problem  NO EQUATION = NO POINTS      c.  Solve d.  Clearly write out your answer(s).