Technology: Smartphones With more advanced applications being developed on mobile devices, some researchers claim that there has been a significant variation in the amount of daily smartphone usage by adult users. Let x represent the amount of hours an adult spends using their smartphone. Suppose, in the United States alone, the population variance of x is approximately s 2 5 2.25.

However, a random sample of 30 adults in a metropolitan city show that x has a sample variance of s2 5 4.12. Use a 5% level of significance to test the claim that the variance of smartphone usage is greater than 2.25. Find a 95% confidence interval for the population variance.

AppendixLO1