The mean life of a particular brand of light bulb is 1200 hours. if you know that at about 95% of this brand of bulbs will last between 1100 and 1300 hours, then what is the standard deviation of the light bulbs’ life?

a) 200
b) 100
c) 50
d) 25
e) 75

c) 50

Step-by-step explanation:

We have been given that the mean life of a particular brand of light bulb is 1200 hours. About 95% of this brand of bulbs will last between 1100 and 1300 hours.

We will use z-score formula to solve our given problem.

, where,

,

,

,

We know that 95% of data points lies within two standard deviation of mean, so 1100 will correspond to a z-score of -2 and 1300 will correspond to a z-score of 2.

We can use sample score 1300 and get same answer as:

Therefore, the standard deviation of the light bulbs’ life is 50 years.

step-by-step explanation:

ok one would be money, and the other would be refreshments or something similar. if each bag of popcorn is 5.00 and each drink is half of that that means drinks are 2.50 the proper way to do that would to look and see how much of each you can buy without exceeding a limit of 30.00

christopher is 272,195 year old

step-by-step explanation: