Question

# A study of the ages of motorcyclists killed in crashes involves the random selection of 132...

A study of the ages of motorcyclists killed in crashes involves the random selection of 132

drivers with a sample mean of 32.95 years. Assume that the population standard deviation is 9.4 years. a) Find the critical value zα /2 for a 94% confidence interval

b) Construct and interpret the 94% confidence interval estimate of the mean age of all motorcyclists killed in crashes. Use the z-table method.

c) Use TI84/83 calculator method.
d) Write a conclusion about the confidence interval.

A.

= 1.881

B.

C.

Follow the below stop to calculate the confidence interval:

Press [STAT]->Calc->7. Z-interval [ENTER]

D.

Therefore, based on the data provided, the 94% confidence interval for the population mean is 31.411<μ<34.489, which indicates that we are 94% confident that the true population mean age of all motorcyclists killed in crashes is contained by the interval (31.411,34.489).

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