Afternoon everyone
I have two probability questions I have had a go at, Can someone have a look and see if they are correct or where i'm gonig wrong.
Mean length 10cm s.d 4mm - Bar 1
Mean length 20cm sd 6mm - Bar 2
So probability of picking bar 1 & bar 2 at randomand the total length being greater than 30.8cm
so add mean[FONT=MathJax_Math-italic] =[/FONT] 30cm
s.d =1cm
(30.8-30)/1
=0.8
using z table = 0.2119
Also difference in length of two random bars from the same as above being less than 9.8,
so Minus then
mean=10cm
s.d = 0.2cm
(9.8-10)/0.2
=-1
using -z table i get = 0.1587
sorry not used correct symbols on phone and doesn't seem to want to work.
Can somebody check these are correct.
thanks
Andy
I have two probability questions I have had a go at, Can someone have a look and see if they are correct or where i'm gonig wrong.
Mean length 10cm s.d 4mm - Bar 1
Mean length 20cm sd 6mm - Bar 2
So probability of picking bar 1 & bar 2 at randomand the total length being greater than 30.8cm
so add mean[FONT=MathJax_Math-italic] =[/FONT] 30cm
s.d =1cm
(30.8-30)/1
=0.8
using z table = 0.2119
Also difference in length of two random bars from the same as above being less than 9.8,
so Minus then
mean=10cm
s.d = 0.2cm
(9.8-10)/0.2
=-1
using -z table i get = 0.1587
sorry not used correct symbols on phone and doesn't seem to want to work.
Can somebody check these are correct.
thanks
Andy