Tbh not completely sure but I think its 180 .
Answer:
A. frequency table
Step-by-step explanation:
In probability, which is the study of events which may or may not occur, the frequency distribution table shows <em>the </em><em>numerical</em><em> </em><em>value</em><em> </em><em>which </em><em>is </em><em>assigned</em><em> </em><em>to </em><em>the </em><em>likelihood</em><em> </em><em>of </em><em>an </em><em>event </em><em>and </em><em>the </em><em>probability</em><em> </em><em>of </em><em>occurrence </em><em>of </em><em>the </em><em>event.</em>
The probability that the student does not know the answer but he randomly guesses it is 0.146025
<h3>How to solve for the probability of having a correct guess</h3>
The question has only one right answer out of 5 choices.
Probability he answers incorrectly:
1 - 0.55 * 4/5
= 0.45 * 0.8
= 0.36
Probability he does not know answer but answers the question correctly

= 0.09/0.55+0.09
= 0.140625
Read more on probability here: brainly.com/question/24756209
Answer:
try doing it on your own so you can get better at it
Answer:
Mean = 339 hours
Standard deviation = 54 hours
Step-by-step explanation:
We are given that approximately 2.5% of the bulbs have lives exceeding 445 hours
So,P(x>445) = 0.025
P(x<445) =1- 0.025 =0.975
z value for 0.975 is 1.96
Formula : 
So, 
--A
Now we are given that approximately 16% have lives exceeding 393 hours,
So,P(x>393) = 0.16
P(x<393) =1- 0.16 =0.84
z value for 0.84 is 1
Formula : 
So, 
---B
Solve A and B
Substitute the value of
from B in A






Substitute the value in B

So, mean = 339 hours
Standard deviation = 54 hours