The temperature reading from a thermocouple placed in a constant-temperature medium is normally distributed with mean μ, the actual temperature of the medium, and standard deviation σ. what would the value of σ have to be to ensure that 95% of all readings are within 0.5° of μ? (round your answer to four decimal places.) σ =

 0.2551

Step-by-step explanation:

Given : The temperature reading from a thermocouple placed in a constant-temperature medium is normally distributed with mean μ, the actual temperature of the medium, and standard deviation σ.

Significance level :

The critical z-value for 95% confidence : (1)

Since , (where x be any random variable that represents the temperature reading from a thermocouple.)

Then, from (1)

    (2)

Also,  all readings are within 0.5° of μ,

i.e.

i.e.   [From (2)]

i.e.  

i.e.

The required standard deviation :

for the first question it would be the second answer for the second question it would be the third answer and for the third question it would be the first answer

step-by-step explanation:

d is the correct answer

step-by-step explanation:

x= 8 because 3x = 3 * 8, and 3*8 = 24