1.Resistance training is a popular form of conditioning aimed at enhancing sports performance and is widely used among high school, college, and professional athletes, although its use for younger...

1.Resistance training is a popular form of conditioning aimed at enhancing sports performance and is widely used among high school, college, and professional athletes, although its use for younger athletes is controversial. A random sample of 4200 patients (age 8–30) admitted to U.S. emergency rooms with the code "weightlifting" were obtained. These injuries were further classified as "accidental" if caused by dropped weight or improper equipment use. Of the 4200 weightlifting injuries, 1530 were classified as accidental.


Give a 90% confidence interval for the proportion of weightlifting injuries in this age group that were accidental. Round your answers to three decimal places.
 ? to  ?

2.A study of the effect of exposure to color (red or blue) on the ability to solve puzzles used 42 subjects. Half the subjects (21) were asked to solve a series of puzzles while in a red-colored environment. The other half were asked to solve the same series of puzzles while in a blue-colored environment. The time taken to solve the puzzles was recorded for each subject. To compare the mean times for the two groups of subjects using statistical procedures, what is thedegrees of freedom?
d.f.  ?

3.A study of commuting times reports the travel times to work of a random sample of 1066 employed adults in Chicago. The mean is x = 53.0 minutes and the standard deviation iss = 47.9 minutes. What is the standard error of the mean? (Round your answer to four decimal places.)
 minutes