1) a light bulb producing company states that its lights will last an average of 1200 hours with a standard deviation of 200 hours. a sample of 100 light bulbs from the company were tested and the researcher found that the average life of each light bulb was 1050 hours. at a 95% confidence level, determine whether these light bulbs are in compliance with the company's claim.

The mean ( average ) is given as 1200 hours.

The standard deviation is 200, sample size is 100.

Find the standard error:

√(200^2 / 100) = 20

Now calculate the confidence interval. For 95% the Z number is 1.96

Multiply Z by the standard error:

1.96 x 20 =39.2

Now find the range that the mean should be within:

1200 - 39.2 = 1160.8

1200 + 39.2 = 1239.2

The samples should be between 1160.8 and 1239.2 for a 95% confidence interval.

Since the average was 1050, which is below 1160.8 the bulbs are not in compliance.

do your own work and don"t cheat.

step-by-step explanation:

answer:   35 % is the probability of a late departure or an early arrival.

step-by-step explanation:

let l represents the late departure and e represents the early departure.

then, according to the question,

p(l) = 12 %,   p(e) = 27 % and = 4 %

and, we have to find out,

but, we know that,

which is the required equation that will use to find the probability of a late departure or an early departure.

therefore,   the probability of a late departure or an early arrival =   35 %