Please help I'm really stuck!

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81

The average daily maximum temperature for laura’s hometown can be modeled by the function f(x)=4.5sin(πx/6)+11.8 , where f(x) is the temperature in °c and x is the month. x = 0 corresponds to january.what is the average daily maximum temperature in may? round to the nearest tenth of a degree if needed.use 3.14 for π .

Lana's family entered a 5-kilometer race lana's average step length is about 0.5 meter how many steps will she need to take the finish