A random sample of 16 ATM transactions at the Last National Bank of Flat Rock revealed a mean transaction time of 2.8 minutes with a standard deviation of 1.2 minutes. The width (in minutes) of the 95 percent confidence interval for the true mean transaction time is plus/minus (to three decimal places):

The  width is  

Step-by-step explanation:

From the question we are told that

    The  sample size is  n = 16    

      The mean time is      

     The standard deviation is  

Generally the degree of freedom is mathematically represented as  

=>      

=>    

From the question we are told the confidence level is  95% , hence the level of significance is    

=>  

Generally from the t distribution table the critical value  of   at a degree of freedom of  df = 15 is  

Generally the margin of error is mathematically represented as  

=>    

=>    

Generally the width the confidence 95% confidence interval  

=>    

=>    

he spend 5.1 minutes chatting with his friends

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5 1/10