In a normal distribution what percent of values fall within one standard deviation of the mean?

19.1%
15%
30%
68.2%

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers

Asystem of equations has 1 solution.if 4x-y=5 is one of the equations , which could be the other equation ?

Which type of graph would allow us to compare the median number of teeth for mammals and reptiles easily