A study of the amount of time it takes a mechanic to rebuild the transmission for a 2005 Chevrolet Cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hours. If 40 mechanics are randomly selected, find the probability that their mean rebuild time exceeds 8.7 hours. a) (1pt) Define x-bar:  b) (1pt) Explain why  x-bar is normal c)  (3pts) Find the probability that their mean rebuild time exceeds 8.7 hours. 

Use the given degree of confidence and sample data to construct a confidence interval for the population mean μ. Assume that the population has a normal distribution. Construct a 98% confidence interval for the population mean, μ of the repair bill. Assume the population has a normal distribution. A study of 14 car owners showed that their average repair bill was $192 with a standard deviation of $8. Show work for the all the steps below. (2pts) Point estimate  (3pts) Critical value (round to 3 decimal places): (3pts) Margin of Error (round to 3 decimal places) : (3pts) CI (round to a whole number): (1pt) Interpretation:  

Which carbon isotope is the rarest?

An advantage of the accelerator mass spectrometer (AMS) method of radiocarbon dating is:

 Plants that are of similar ages and that grew in the same soil could produce different radiocarbon ages due to:

Seriation diagrams resemble battleships because:

 _______________ evidence usually provides dates for historical sites.

What exactly does dendrochronology attempt to date?

Absolute dates are absolute in that they

Dating techniques tell us _____________ about cultural activities.