The average lifetime of a light bulb is 3,000 hours with a standard deviation of 696 hours. a simple random sample of 36 bulbs is taken.
a. what are the expected value, standard deviation, and shape of the sampling distribution of ?
b. what is the probability that the average life in the sample will be between 2,670.56 and 2,809.76 hours?
c. what is the probability that the average life in the sample will be greater than 3,219.24 hours?
d. what is the probability that the average life in the sample will be less than 3,180.96 hours?

i think it's ф or x=6,-6

step-by-step explanation:

-x^2=-36

x^2=-36

ф

or

if you mean by : -(x^2)=-36

it'll be: x^2=36

x=6,x=-6

hope it'll ! have a good day!

you for asking!

15%

step-by-step explanation:

use the table and count the number of guesses that has two correct answers.

the following are two correct answers

10010, 01100, 11000

a total of 3 numbers having 2 correct guesses out of 20 questions.

probability of getting 2 correct guesses = the number of questions getting 2 correct answers / total number of questions.

= 3/20

to convert it into percent multiply by 100, we get

= 3/20 * 100

= 15%

the answer is 15%

you.