Answer:
The answer is "0.0764"
Step-by-step explanation:
Please find the complete question in the attached file.
[tex]\to \mu = \$ \ 4064\\\\\to \sigma = \$ \ 460 \\\\\to \sigma \bar{x} = \frac{\sigma}{\sqrt{n}}\\\\[/tex]
[tex]= \frac{460}{\sqrt{21}}\\\\ = \frac{460}{4.58257569}\\\\=100.3802[/tex]
[tex]\to P(\bar{x}< \$ \ 3920) = \frac{P((\bar{x} - \mu \bar{x})}{\frac{\sigma \bar{x}<(3920 - 4064)}{100.3802)}}[/tex]
[tex]\to P(z < -1.43) = 0.0764 \\\\\to P(\bar{x}< \$ \ 3920) = 0.0764\\\\[/tex]