A student researcher measured the cadmium (Cd2+) content in a standard reference material (SRM) using graphite furnace atomic absorption spectrometry (GFAAS). With 7 replicate measurements, the researcher determined a mean Cd2 concentration of 2.899 ppb with a standard deviation of 0.001 ppb. Calculate the 99% confidence interval for this sample. Enter your answer with three significant figures.

The 99% confidence interval for this sample mean is between 2.895 ppb and 2.903 ppb.

Step-by-step explanation:

We have the standard deviation for the sample, so we use the t-distribution to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 7 - 1 = 6

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 6 degrees of freedom(y-axis) and a confidence level of . So we have T = 3.7074

The margin of error is:

M = T*s = 3.7074*0.001 = 0.004

In which s is the standard deviation of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 2.899 - 0.004 = 2.895 ppb.

The upper end of the interval is the sample mean added to M. So it is 2.899 + 0.004 = 2.903 ppb.

The 99% confidence interval for this sample mean is between 2.895 ppb and 2.903 ppb.

d

step-by-step explanation:

the 2000 florida legislature amended section 322.05, florida statutes, changing the requirements to obtain a class e license for a driver under the age of 18 holding a learner's license. the following requirements must be met in order to obtain a regular class e license if a learner's license is issued on or after october 1, 2000:

must hold a learner's license for at least 12 months or until the 18th birthday.

must have no convictions 12 months from the issue date of the learner's license.

may have one traffic conviction within 12 months from the issue date of the learner's license if adjudication is withheld.

a parent, legal guardian, or responsible adult over 21 years old must certify that the driver has 50 hours driving experience, including 10 hours of night time driving.