Aconsumer claims that the mean lifetime of a brand of fluorescent bulbs is less than1500 hours. she selects 25 bulbs and finds the mean lifetime to be 1480 hours with the standard deviation of 80 hours. if you were to test the consumer's claimat the 0.05 significance level, what would you conclude?

We conclude that the mean lifetime of a brand of fluorescent bulbs is equal to 1500 hours.

Step-by-step explanation:

We are given the following in the question:  

Population mean, μ = 1500 hours

Sample mean, = 1480 hours

Sample size, n = 25

Alpha, α = 0.05

Sample standard deviation, s = 80 hours

First, we design the null and the alternate hypothesis

We use one-tailed(left) t test to perform this hypothesis.

Formula:

Putting all the values, we have

Now,

Since,                    

We fail to reject the null hypothesis and accept the null hypothesis.

We conclude that the mean lifetime of a brand of fluorescent bulbs is equal to 1500 hours.

step-by-step explanation:

1. practice, practice & more practice

2. review errors

3. master the key concepts

do not try to memorise the processes.

4. understand your doubts.

5. create a distraction free study environment

6. create a mathematical dictionary

7. apply maths to real world problems.

a - base

b - exponent

so,