takes 1 hour and 21 minutes for a 2.00 mg sample of radium-230 to decay to 0.25 mg. What is the half-life of radium-230?

1. there are 25 students who started computer programming in elementary school and 25 students who started computer programming in middle school. the first group had a mean final project grade of 95% and the second group had a mean final project grade of 92%. the line plot shows the differences after 10 rerandomizations. determine whether the difference in the means of the two groups is significant based on the line plot. explain your answer.

Jose bought 20 shares of netflix at the close price of $117.98. in a few years, jose sells all of his shares at $128.34. how much money did jose make? a.) $192.50 b.) $207.20 c.) $212.50 d.) $224.60

Suppose sat writing scores are normally distributed with a mean of 497 and a standard deviation of 109. a university plans to award scholarships to students whose scores are in the top 2%. what is the minimum score required for the scholarship? round your answer to the nearest whole number, if necessary.