Answer:
"0.0125" is the right solution.
Step-by-step explanation:
The given values are:
Random sample,
n = 90
Claims,
p = 20%
or,
= 0.20
By using normal approximation, we get
⇒ [tex]\mu = np[/tex]
On substituting the values, we get
⇒ [tex]=90\times 0.20[/tex]
⇒ [tex]=18[/tex]
Now,
The standard deviation will be:
⇒ [tex]\sigma=\sqrt{np(1-p)}[/tex]
On putting the above given values, we get
⇒ [tex]=\sqrt{90\times 0.20\times (1-0.20)}[/tex]
⇒ [tex]=\sqrt{18\times 0.8}[/tex]
⇒ [tex]=\sqrt{14.4}[/tex]
⇒ [tex]=3.7947[/tex]
hence,
By using the continuity correction or the z-table, we get
⇒ [tex]P(x < 10) = P(x < 9.5)[/tex]
⇒ [tex]P(x < 10) = P(\frac{x-\mu}{\sigma} -\frac{9.5-18}{3.7947} )[/tex]
⇒ [tex]P(x < 10) = P(Z < -2.24)[/tex]
From table,
⇒ [tex]P(x < 10) = 0.0125[/tex]
