Answer:
Step-by-step explanation:
given that certain tubes manufactured by a company have a mean lifetime of 800 hours and a standard deviation of 60 hours.
Sample size n =16
Std error of sample mean = 
x bar follows N(800, 15)
the probability that a random sample of 16 tubes taken from the group will have a mean lifetime
(a) between 790 and 810 hours,
=
(b) less than 785 hours

, (c) more than 820 hours,

(d) between 770 and 830 hours
=
Answer:
B
Step-by-step explanation:
I Had this
60 degrees because vertical angles are congruent if you move line y 5 degrees clockwise then you are adding 5+55=60 and since 1 and 3are congruent 3=60 degrees
Answer:
she was wrong
Step-by-step explanation:
x-4-11 = 0 (4+-1=4-1)
x=15
hence she was wrong