According to a national Gallup Poll of U.S. smartphone users, 75% upgrade their cell phone every two years.

Use this information to answer the following questions. Show all required work. Be sure to include your probability and calculator statements for the questions where indicated.

A. Determine the probability (to 4 decimal places) that exactly 6 users out of 14 smartphone users do not upgrade their cell phones every two years

i) Rewrite this question using probability notation: P( ) where X = users
ii) Determine this probability & list TI 83/84 function w/values used to compute this probability:

B. Determine the probability (to 4 decimal places) that at most 5 users of 14 smartphone users upgrade their cell phones every two years.

i) Rewrite this question using probability notation: P( ) where X = users

ii) Determine this probability & list TI 83/84 function w/values used to compute this probability:

C. Determine the probability (to 4 decimal places) that between 7 and 9 users, inclusive, of the 14 smartphone users do not upgrade their cell phones every two years.
i) Rewrite this question using probability notation: P( ) where X = users
ii) Determine this probability & list TI 83/84 function w/values used to compute this probability:

D. Determine the probability (to 4 decimal places) that at least 1 user out of the 14 smartphone users do not upgrade their cell phones every two years.
i) Rewrite this question using probability notation: P( ) where X = users
ii) Determine this probability & list TI 83/84 function w/values used to compute this probability:

E. Would it be unusual if more than 13 of the 14 smartphone users upgrade their cell phones every two years? Explain why or why not. You MUST support your answer with pertinent probability calculations.
i) Rewrite this question using probability notation: P( ) where X = users