A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. The mean is found to be 9.8 reproductions and the population standard deviation is known to be 2.4. If a sample of 955 was used for the study, construct the 99% confidence interval for the true mean number of reproductions per hour for the bacteria. Round your answers to one decimal place.

The 99% confidence interval for the true mean number of reproductions per hour for the bacteria is between 9.6 and 10.

Step-by-step explanation:

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

So it is z with a pvalue of , so

Now, find the margin of error M as such

In which is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 9.8 - 0.2 = 9.6 reproductions per hour.

The upper end of the interval is the sample mean added to M. So it is 9.8 + 0.2 = 10 reproductions per hour.

The 99% confidence interval for the true mean number of reproductions per hour for the bacteria is between 9.6 and 10.

  21.3

step-by-step explanation:

multiplying the given equation by c/sin(25°), we get

  c = 9/sin(25°) ≈ 21.2958 ≈ 21.3

we assume "c" is the length of ab, the side opposite angle c in triangle abc.