5.   Teachers’ an average salary of $35,270, with a standard deviation of $3256. A sample of 30 teachers from New York has an average salary of $29,512, with a standard deviation of $1432. Is there a significant difference in teachers’ salaries between the two states? Use a = 0.02. Find the 98% confidence interval for the difference of the two means.

6.   Soft Drinks in School The data show the amounts

(in thousands of dollars) of the contracts for soft drinks in local school districts. At a = 0.10 can it be concluded that there is a difference in the averages? Use the

P-value method. Give a reason why the result would be of concern to a cafeteria manager.

 

 

 

 

 

9.  

78 82 68 67 68 70 74 73 60 77 75 73 75 64 68 71 72 71 74 76 62 73 77 78 79 71 80 65 70 83 74 72 73 78 68 67 76 75 62 65 73 79 82 71 66 66 65 77 66 64   Â

Foggy Days St. Petersburg, Russia, has 207 foggy days out of 365 days while Stockholm, Sweden, has 166 foggy days out of 365. At a = 0.02, can it be concluded that the proportions of foggy days for the two cities are different? Find the 98% confidence interval for the difference of the two proportions.

Source: Jack Williams, USA TODAY.