A computer manufacturer estimates that its line of minicomputers has, on average, 7.2 days of downtime per year. To test this claim, a researcher contacts seven companies that own one of these computers and is allowed to access company computer records. It is determined that, for the sample, the average number of downtime days is 4.4, with a sample standard deviation of 1.1 days. Assuming that number of downtime days is normally distributed, test to determine whether these minicomputers actually average 7.2 days of downtime in the entire population. Let α = .01.

The average of minicomputers is not 7.2 days of downtime per year.

Step-by-step explanation:

We are given the following in the question:  

Population mean, μ = 7.2 days

Sample mean, = 4.4 days

Sample size, n = 7

Alpha, α = 0.01

Sample standard deviation, s = 1.1 days

First, we design the null and the alternate hypothesis

We use two-tailed t test to perform this hypothesis.

Formula:

Putting all the values, we have

Now,

Since,                        

Since, the calculated t-statistic does not lie in the acceptance region, we fail to accept the null hypothesis and reject it. We accept the alternate hypothesis.

Conclusion:

Thus, we conclude there is not enough evidence to support the claim that minicomputers actually average 7.2 days of downtime in the entire population.

ddd

step-by-step explanation:

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m