Question

In: Statistics and Probability

A random survey of 75 death row inmates revealed that the mean length of time on...

A random survey of 75 death row inmates revealed that the mean length of time on death row is 17.4 years with a standard deviation of 6.8 years. Conduct a hypothesis test to determine if the population mean time on death row could likely be 15 years.

State the distribution to use for the hypothesis test. (Enter your answer in the form z or tdf where df is the degrees of freedom.)

Find the p-value. (Round your answer to four decimal places.)

What is the population standard deviation?

Solutions

Expert Solution

Solution :

Given that ,

The distribution to use for the hypothesis test is Z

= 15  

= 17.4

= 6.8

n = 75

The null and alternative hypothesis is ,

H0 :   = 15

Ha :    15

This is the two tailed test .

Test statistic = z

= ( - ) / / n

= ( 17.4 - 15 ) / 6.8 / 75

= 3.06

The test statistic = 3.06

P - value = 2 * P(Z > 3.06 ) = 2 * 1- P (Z < 3.06 )

= 2 * 0.9989

= 0.0011

P-value = 0.0011

The population standard deviation is 6.8 years.


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