g In an experiment, 37 randomly selected drivers drove from Pontiac to Detroit at random times. The travel time for these drivers was 39.0 minutes on average with a standard deviation of 4.8 minutes. Calculate and interpret a 99.9% confidence interval for the mean travel time for all possible drivers traveling from Pontiac to Detroit.

CI  = ( 36,6  ;  41,4 )

Step-by-step explanation:

CI = 99,9  %       α = 0,1 %      α = 0,001

We find z scre for α = 0,001 in z -table

z(s) = - 3,08

CI =  μ₀  ±  MOE          where    μ₀  = 39 min  and   MOE = z(s) * σ/√n

CI = 39  ±   3,08 * 4,8 / √37

CI = 39  ±   2,4315

CI  = ( 36,6  ;  41,4 )

answer: cos [   arcsin (3/5) - arccos (1/2) ] =

step-by-step explanation: × = 3/5 = 0.6--> x = 36.87 and x = 180 - 36.87 = 143.13 deg

cos y = 1/2 --> y = +- 60 deg a. cos (x - y) = cos (143.13 - 60) = cos 83,13  

=

0.12

b. cos (36.87 - 60) = cos (-23.23) = 0.92