#1**+1 **

While your composing that one I would like to post this one as well. I am confused on this one too

jjennylove Apr 5, 2019

#2**0 **

We want to find the z score in the table that corresponds to .20 [ or....at least as close as possible]

Looking at the table here : http://www.z-table.com/ .... we find that this corresponds to a z score of ≈ -.84

So....the 'formula" for our z score is

[ mass we are trying to find - mean ]

________________________________ = -.84 fill in what we know

std dev

[ mass we are trying to find - 55 ]

_______________________________ = -.84 multiply both sides by 4.2

4.2

mass we are trying to find - 55 = -3.528 add 55 to both sides

mass we are trying to find = 51.472 ≈ 51.5 g [ first answer ]

EDIT TO CORRECT A PREVIOUS ERROR !!!

CPhill Apr 5, 2019

#5

#4**0 **

Second one

[ age we are looking for - mean ]

____________________________ = z score

std dev

[age we are looking for - 32 ]

___________________________ = -1.2 multiply both sides by 6.2

6.2

age we are looking for - 32 = -7.44 add 32 to both sides

age we are looking for = 24.56 = 24.6 rounded to nearest tenth

CPhill Apr 5, 2019