Historically, the average time a customer takes with a teller at a particular bank was 130 seconds ...

  

Historically, the average time a customer takes with a teller at a particular bank was 130 seconds. To determine whether the average time with the teller had changed since they changed the staff manager, the bank undertook a random sample of the waiting time (in seconds) recorded by 11 customers.The results are in the X2 column of the data file 

  

57

10.4

143

 

68

9.6

147

 

74

9.8

128

 

81

8.4

119

 

82

8.8

130

 

86

8.9

135

 

101

8.1

141

 

112

7.6

123

 

114

7.8

121

 

119

7.4

129

 

124

6.4

135

Assume that the test is performed at the 5% level of significance and that the distribution of waiting times is approximately normally distributed.

1. State the direction of the alternative hypothesis used to test whether average waiting time had changed. Type gt (greater than), ge (greater than or equal to), lt (less than), le (less than or equal to) or ne (not equal to) as appropriate in the box.
2. Calculate the test statistic correct to three decimal places (hint: use Descriptive Statistics to calculated the standard deviation and sample mean).
3. Use KaddStat to determine the p-value for the test correct to three decimal places.  
4. Is the null hypothesis rejected for this test? Type yes or no.
5. Regardless of your answer for 4, if the null hypothesis was rejected, could we conclude that the average time is not 130 seconds at the 5% level of significance? Type yes or no.