statistics
posted by Catherine .
Write the null and alternative hypotheses. Justify which is the claim. A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is less than 900 hours

The claim: mean < 900
other option: mean > or = 900
The null hypothesis is the one with an equal sign...
Your null hypothesis would be mean=900
Your alt. hypothesis would be mean<900
The alt. hypothesis is the claim.
Respond to this Question
Similar Questions

college
a light bulb manufacture claims that the mean life of a certain type of light bulb is more than 750 hours 
statitics
a light bulb manufacture gaurentees that the mean life of a certain type of bulb is at least 875 hours. A random sample of 40 light bulbs has a mean life of 863 hours with a standard deviation of 50. a=0.04 
statistics
the life of light bulbs is distributed normally. The variance of the life time is 225 and the mean lifetime of a bulb is 590 hours. Find the probability of a bulb lasting for at most 603 hours. Yeah, WTF? 
statistics
Suppose that the certain lifetimes of a certain light bulb are normally distributed with μ=1500 hours and σ=200. Find the probability that a light bulb will burn out in less than 1200 hours. 
math
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 … 
Statistics
An electrical firm which manufactures a certain type of bulb wants to estimate its mean life. Assuming that the life of the light bulb is normally distributed and that the standard deviation is known to be 40 hours, how many bulbs … 
Statistics
The life of an electric light bulb is known to be normally distributed with a mean of 2000 hours and a std. of 120 hours. Find the probability that the life of such a bulb would be. (a) greater than 2150 hours (b) within the range … 
Business Statistics
The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The manufacturer's specifications are that the standard deviations is 100 hours. A random sample of 64 light bulbs … 
maths
the life span of an electric bulb is normally distribution with mean 5500 light hours and standard deviation of 1200 light hours . what is the probability that a randomly selected bulb which lasts more than 6000 light hours? 
math
If the variance of a light bulb is 400 and the mean lifetime of a light bulb is 600 hours. find the probablity of a light bulb lasting at most 622 hours