The mean length of a cellular telephone call in 1999 was 2.38 minutes. A researcher claims that the average length of a phone call has increased since then. She conducts a survey of randomly selected 49 cellular phone users and determines the mean length to be 2.48 minutes, and standard deviation 1.8 minutes. To test the claim we would use:

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Step-by-step explanation:

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use an equation of ratios to determine the amount of gas needed to fill the tank.

    0.2             0.8

  =    

288.75             x

                                                              231 gal

so, 0.2x = (0.8)(288.75 gal), and x = = 1155 gal.

                                                                0.2

it would take 1155 gal. to fill the tank.

the cost would be

1155 gal         $3

* = $3465   (answer)

      1           1 gal

hope this you

i got 142 as my answer

step-by-step explanation: