SOLUTION: Good evening guys, I need help with this question, thank you in advance!!!
A study has shown that 20% of all college textbooks cost at least $70. It is known that the standard d
Algebra ->
Finance
-> SOLUTION: Good evening guys, I need help with this question, thank you in advance!!!
A study has shown that 20% of all college textbooks cost at least $70. It is known that the standard d
Log On
Question 871441: Good evening guys, I need help with this question, thank you in advance!!!
A study has shown that 20% of all college textbooks cost at least $70. It is known that the standard deviation of the prices of the college textbook is $9.50. Assuming that prices of all college textbooks follows a normal distribution; find the mean price of all college textbooks.
This is what I did so far.
x= cost of textbook x~normal (M, SD= 9.50)
P(x>70)=20%
P(x<70)=80%
P(z<70-M)=.8000
-------
9.50 Answer by Yzeph(21) (Show Source):
(