
Respuesta :
Answer:
a
 [tex]P(X  < 35) =  32.3 \%[/tex]
b
[tex]P(\= X Â < 35) = Â 0.6 \%[/tex]
Here the probability of koalas mean temperature being less than 35 °C is very small hence the koalas are not healthy
c
A potential confounding variable for this study is  the population of the koalas because in the first question the population was not taken into account and the probability was  [tex]P(X  < 35) =  32.3 \%[/tex] but when the population was taken into account (i.e  n =  30) the probability became
[tex]P(\= X Â < 35) = Â 0.6 \%[/tex] Â
Step-by-step explanation:
From the question we are told that
 The mean is  [tex]\mu =  35.6^oC[/tex]
  The standard deviation is  [tex]s =  1.3^oC[/tex]
  The sample size is  n = 30
Generally the  probability that a health koala has a body temperature less than 35.0°C is mathematically represented as
   [tex]P(X  < 35) =  P(\frac{X  - \mu }{s}  < \frac{35 - 35.6}{1.3} )[/tex]
Here  [tex](\frac{X  - \mu }{s} =  Z (The  \ standardized \  value \  of  \  X )[/tex]
So
  [tex]P(X  < 35) =  P(Z < -0.46)[/tex]
From the z-table  P(Z <  -0.46) =  0.323
So Â
  [tex]P(X  < 35) =  0.323 [/tex]
Converting to percentage
   [tex]P(X  < 35) =  0.323  * 100 [/tex]
   [tex]P(X  < 35) =  32.3 \%[/tex]
considering question b
The sample mean is  [tex]\= x =  35[/tex]
Generally the standard error of the mean is mathematically represented as
  [tex]\sigma_{\= x} =  \frac{s}{\sqrt{n} }[/tex]
=> Â [tex]\sigma_{\= x} = Â \frac{1.3}{\sqrt{30} }[/tex]
=> Â [tex]\sigma_{\= x} = Â 0.2373 [/tex]
Generally the probability of the mean body temperature of koalas being less than 35.0°C is mathematically represented as
 [tex]P(\= X  < 35) =  P(\frac{\= X  -  \mu  }{\sigma_{\= x }} <  \frac{35 -35.6}{0.2373 }  )[/tex]
[tex]P(\= X Â < 35) = Â P(Z< -2.53 Â )[/tex]
From the z-table  we have that
  [tex]P(Z< -2.53  ) =  0.006[/tex]
So
 [tex]P(\= X  < 35) = 0.006 /tex]
Converting to percentage
   [tex]P(\= X  < 35) =  0.006  * 100 [/tex]
   [tex]P(\= X  < 35) =  0.6 \%[/tex]
Here the probability of koalas mean temperature being less than 35 °C is very small hence the koalas are not healthy
A potential confounding variable for this study is  the population of the koalas because in the first question the population was not taken into account and the probability was  [tex]P(X  < 35) =  32.3 \%[/tex] but when the population was taken into account (i.e  n =  30) the probability became
 [tex]P(\= X  < 35) =  0.6 \%[/tex] Â