In spring 2017, data was collected from a random selection of sta 2023 students. one of the questions asked how many hours they had volunteered in the past 24 hours. for the 39 randomly selected upperclassmen, the sample mean was 0.12 and sample standard deviation was 0.42. for the 35 randomly selected underclassmen, the sample mean was 0.34 and the sample standard deviation was 0.87. what is the point estimate of the difference in the population mean volunteered between underclassmen and upperclassmen?

i dont know

step-by-step explanation:

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.