Assume that the readings on the thermometers are normally distributed with a mean of 0 C and a standard deviation of 1 C. A thermometer is randomly selected and tested. If 1.7% of the thermometers are rejected because they have readings that are too low, but all other thermometers are acceptable, find the reading that separates the rejected thermometers from the others.

Respuesta :

Answer: -2.12°C

Step-by-step explanation:

Let x denotes the reading of the thermometers .

We assume that the readings on the thermometers are normally distributed.

Let a be the reading that separates the rejected thermometers from the others.

Given: Population mean : [tex]\mu=0[/tex]

Standard deviation: [tex]\sigma= 1[/tex]

Also, [tex]P(x<a)=0.017[/tex]

By using the z-table , the z-value corresponds to the p-value (one -tailed)0.017 is [tex]\pm2.12[/tex].

Now, [tex]z=\dfrac{a-\mu}{\sigma}[/tex]

i.e. [tex]\pm2.12=\dfrac{a-0}{1}[/tex]

i.e. [tex]\pm2.12=a[/tex]

For left tailed , [tex]a=-2.12[/tex]

It means the reading that separates the rejected thermometers from the others = -2.12°C.